[binutils-gdb/gdb-8.0-branch] Bump GDB version number to 7.99.91.DATE-git.

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 65ea01b5924c8ed220368def5dde3151d071d6df ***

Author: Joel Brobecker <brobecker@adacore.com>
Branch: gdb-8.0-branch
Commit: 65ea01b5924c8ed220368def5dde3151d071d6df

Bump GDB version number to 7.99.91.DATE-git.

gdb/ChangeLog:

	* version.in: Set GDB version number to 7.99.91.DATE-git.
	* PROBLEMS: Likewise.