bug#30258: 26.0.90; url-file and url-data don't load mm-misc

[Noam Postavsky <npostavs@users.sourceforge.net>]

emacs -Q

    (url-data (url-generic-parse-url "data:;,A-brief-note"))

gives

Debugger entered--Lisp error: (void-function mm-disable-multibyte)
  mm-disable-multibyte()
  url-data(#s(url :type "data" :user nil :password nil :host nil :portspec nil :filename ";,A-brief-note" :target nil :attributes nil :fullness nil :silent nil :use-cookies t :asynchronous t))
  eval((url-data (url-generic-parse-url "data:;,A-brief-note")) nil)

Similarly,

    (url-file (url-generic-parse-url "file:///dev/null") #'ignore nil)

Debugger entered--Lisp error: (void-function mm-disable-multibyte)
  mm-disable-multibyte()
  url-file(#s(url :type "file" :user nil :password nil :host "" :portspec nil :filename "/dev/null" :target nil :attributes nil :fullness t :silent nil :use-cookies t :asynchronous t) ignore nil)
  eval((url-file (url-generic-parse-url "file:///dev/null") (function ignore) nil) nil)

This does not occur with Emacs 25.  Will send patch when I have the bug number.