Documentation: git gc packs refs by default now

In commit 5675239 (Make "git gc" pack all refs by default,
2007-05-24), 'git gc' was changed to run pack-refs by default

Versions before v1.5.1.2 cannot clone repos with packed refs over
http, and versions before v1.4.4 cannot handled packed refs at
all, but more recent git should have no problems.  Try to make
this more clear in the git-config manual.

The analagous passage in git-gc.txt was updated already with
commit fe2128a (Change git-gc documentation to reflect
gc.packrefs implementation., 2008-01-09).

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -875,15 +875,12 @@ gc.autopacklimit::
 	default	value is 50.  Setting this to 0 disables it.
 
 gc.packrefs::
-	'git-gc' does not run `git pack-refs` in a bare repository by
-	default so that older dumb-transport clients can still fetch
-	from the repository.  Setting this to `true` lets 'git-gc'
-	to run `git pack-refs`.  Setting this to `false` tells
-	'git-gc' never to run `git pack-refs`. The default setting is
-	`notbare`. Enable it only when you know you do not have to
-	support such clients.  The default setting will change to `true`
-	at some stage, and setting this to `false` will continue to
-	prevent `git pack-refs` from being run from 'git-gc'.
+	Running `git pack-refs` in a repository renders it
+	unclonable by Git versions prior to 1.5.1.2 over dumb
+	transports such as HTTP.  This variable determines whether
+	'git gc' runs `git pack-refs`. This can be set to "nobare"
+	to enable it within all non-bare repos or it can be set to a
+	boolean value.  The default is `true`.
 
 gc.pruneexpire::
 	When 'git-gc' is run, it will call 'prune --expire 2.weeks.ago'.