bug#25881: guix package --remove $PKG downloads and updates other packages

[<dian_cecht@zoho.com>]

Recently I had to remove duplicity from a profile because it doesn't
support hardlinks, and something very interesting happened:


=== start of output ===
guix package --remove duplicity
The following package will be removed:
   duplicity
0.7.11	/gnu/store/3a9ggca9cw4gv69lg8ihi1c6jx2xd92j-duplicity-0.7.11

substitute: warning: 'https_proxy' is ignored
updating list of substitutes from 'https://mirror.hydra.gnu.org'...
100.0%g'...  95.2% The following derivations will be built:
   /gnu/store/s8a6rx3qrgpbw3mrllp2zmijxkrzzgh6-profile.drv
   /gnu/store/46qgf7ws2rcz260sxhxf4bh5a7a3n5ks-mkfontscale-1.1.2.drv
   /gnu/store/3j49ffh3v8dd9al122jfb5kvghrzjlds-module-import.drv
   /gnu/store/4ff02yd8i72pfw5nki15v51abdsnn9vw-module-import-compiled.drv
   /gnu/store/p20nk4l00zywxwbl5fkdrha5ajwc9lw2-mkfontscale-1.1.2.drv
   /gnu/store/z3dq9p2hrv3ihckx3b10hambla1advqq-mkfontdir-1.0.7.drv
   /gnu/store/n4ypy18jmpwpmc591pf80cy6aiw8igsn-fonts-dir.drv
   /gnu/store/a5f32zly8isws5n8jnnrqz97acf0z0qv-texinfo-6.3.drv
   /gnu/store/mlyxjdnwna57v4y38955p3wj67lihn7p-info-dir.drv
   /gnu/store/25l9jdfj56yb8na0wb1khixg1zwq94f2-module-import.drv
   /gnu/store/b7lrgb3dzy9d6l41ya7cy8vnf674qr6y-module-import-compiled.drv
   /gnu/store/275lpklrjq74dwbzlafnlb8rd2xdqvnq-ca-certificate-bundle.drv
   /gnu/store/3jggaks2xcmk72ykgqkl703i07mm3f4s-module-import-compiled.drv
   /gnu/store/5kafw17sff053kk4a80ynvza3vlf2ack-guile-2.0.12.drv
   /gnu/store/hknlvn5319g9pinz6f3r59qjp4b9399g-module-import.drv
The following files will be downloaded:
   /gnu/store/i7228ph97vqbpw8v4m0xmfgnppy149vq-mkfontscale-1.1.2
   /gnu/store/7cvdqkddzbcan5jxwyvsmar0h7wlckik-module-import-compiled
   /gnu/store/sq03gq3lhpwgbiy9k5klnqd2q8z7iwxp-module-import
   /gnu/store/8l77r5ikky0ghm1w9zc2pxfn80rb5n5w-mkfontdir-1.0.7
   /gnu/store/j6k8xgsqrl5v1ajqh3i1wb603rzzg1jg-texinfo-6.3
   /gnu/store/dn9f03l4zh3y35632sv1zppydbag3n17-libfontenc-1.1.3
Downloading
https://mirror.hydra.gnu.org/nar/3qp4y2xf4ra1fmqrnpgivcc8fj1z1mkp-guile-2.0.12-debug
(6.0MiB installed)... warning: 'https_proxy' is ignored
guile-2.0.12-debug
1.5MiB/s 00:01 | 1.6MiB transferred

Downloading
https://mirror.hydra.gnu.org/nar/dn9f03l4zh3y35632sv1zppydbag3n17-libfontenc-1.1.3
(82KiB installed)... warning: 'https_proxy' is ignored
libfontenc-1.1.3
4.5MiB/s 00:00 | 24KiB transferred

Downloading
https://mirror.hydra.gnu.org/nar/sq03gq3lhpwgbiy9k5klnqd2q8z7iwxp-module-import
(928B installed)... warning: 'https_proxy' is ignored
module-import
69KiB/s 00:00 | 268B transferred

Downloading
https://mirror.hydra.gnu.org/nar/i7228ph97vqbpw8v4m0xmfgnppy149vq-mkfontscale-1.1.2
(40KiB installed)... warning: 'https_proxy' is ignored
mkfontscale-1.1.2
2.8MiB/s 00:00 | 19KiB transferred

Downloading
https://mirror.hydra.gnu.org/nar/7cvdqkddzbcan5jxwyvsmar0h7wlckik-module-import-compiled
(82KiB installed)... warning: 'https_proxy' is ignored
module-import-compiled
2.8MiB/s 00:00 | 26KiB transferred

Downloading
https://mirror.hydra.gnu.org/nar/8l77r5ikky0ghm1w9zc2pxfn80rb5n5w-mkfontdir-1.0.7
(4KiB installed)... warning: 'https_proxy' is ignored
mkfontdir-1.0.7
896KiB/s 00:00 | 4KiB transferred

Downloading
https://mirror.hydra.gnu.org/nar/j6k8xgsqrl5v1ajqh3i1wb603rzzg1jg-texinfo-6.3
(8.2MiB installed)... warning: 'https_proxy' is ignored
texinfo-6.3
1.2MiB/s 00:01 | 1.4MiB transferred

grafting
'/gnu/store/3qp4y2xf4ra1fmqrnpgivcc8fj1z1mkp-guile-2.0.12-debug' ->
'/gnu/store/wlfk0g4vjb1qdicyk0p1cdhbgijm2fll-guile-2.0.12-debug'...
grafting '/gnu/store/6slzn4ixcjlhy3av3biglqfli9pwxcn9-guile-2.0.12' ->
'/gnu/store/vmq9sbjjwi57v4wv0ydjwl3c7h3dr6rm-guile-2.0.12'... grafting
'/gnu/store/i7228ph97vqbpw8v4m0xmfgnppy149vq-mkfontscale-1.1.2' ->
'/gnu/store/4v3ddshnwv8aj4gacmchyzhr01asj5n7-mkfontscale-1.1.2'...
grafting '/gnu/store/8l77r5ikky0ghm1w9zc2pxfn80rb5n5w-mkfontdir-1.0.7'
-> '/gnu/store/kxk2mf5wcpia9lg8sq66f8nr3kq4nxg9-mkfontdir-1.0.7'...
grafting '/gnu/store/j6k8xgsqrl5v1ajqh3i1wb603rzzg1jg-texinfo-6.3' ->
'/gnu/store/s5zdanc9qz915fr729a0nidma1i5xm4z-texinfo-6.3'... 6 packages
in profile
=== end of output ===

I don' know why, but removing duplicity effectivly updated other
packages in the profile, which most certainly isn't related to 
uninstalling a package. I don't know if this is how things are meant to
be, but this behavior is entirely unexpected and makes no sense
whatsoever to me (especially since it has literally nothing to do with
uninstalling a program).

If this is the intended behavior, then I think some thoughts on whether
or not this violates the user's right to choose when and how they update
their system is needed.