Documentation: Remove --{min,max}-age option from git-log(1)

The --max-age=<timestamp> and --min-age=<timestamp> are now shown only
in the git-rev-list manpage (plumbing).
Signed-off-by: NJakub Narebski <jnareb@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/rev-list-options.txt

@@ -130,9 +130,11 @@ limiting may be applied.
 
 	Show commits older than a specific date.
 
+ifdef::git-rev-list[]
 --max-age='timestamp', --min-age='timestamp'::
 
 	Limit the commits output to specified time range.
+endif::git-rev-list[]
 
 --author='pattern', --committer='pattern'::