bug#20528: 25.0.50; `keymap' property to work for symbol-value, not just symbol-function

[Drew Adams <drew.adams@oracle.com>]

The `keymap' text or overlay property can have a value that is
`keymapp', which means that it can be a list with car `keymap' etc. or a
symbol whose `symbol-function' is a keymap.

Please allow it to also be a symbol, such as `Info-mode-map', whose
`symbol-value' is a keymap.  It is used only as a keymap.  It is not
used as a function.  It is convenient to be able to reuse an existing
keymap variable to provide a map for a given portion of text.

Likewise, for property `local-map'.

(I'm guessing that I cannot change Emacs to recognize this, myself,
because it involves the C level (e.g. `key-binding' or `lookup-key').
If I'm mistaken, please point me to the Lisp code that interprets
the keymap property, looks up a key in the map and invokes its command.)


In GNU Emacs 25.0.50.1 (i686-pc-mingw32)
 of 2014-10-20 on LEG570
Bzr revision: 118168 rgm@gnu.org-20141020195941-icp42t8ttcnud09g
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --enable-checking=yes,glyphs CPPFLAGS=-DGLYPH_DEBUG=1'