http-backend: use mod_alias instead of mod_rewrite

In the git-http-backend documentation, use mod_alias exlusively, instead
of using a combination of mod_alias and mod_rewrite.  This makes the
example slightly shorted and a bit more clear.

Signed-off-by: Mark Lodato <lodatom@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-http-backend.txt

@@ -98,13 +98,9 @@ Accelerated static Apache 2.x::
 ----------------------------------------------------------------
 SetEnv GIT_PROJECT_ROOT /var/www/git
 
-ScriptAlias /git/        /usr/libexec/git-core/git-http-backend/
+AliasMatch ^/git/(.*/objects/[0-9a-f]{2}/[0-9a-f]{38})$          /var/www/git/$1
-Alias       /git_static/ /var/www/git/
+AliasMatch ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.(pack|idx))$ /var/www/git/$1
-
+ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/
-RewriteEngine on
-RewriteRule ^/git/(.*/objects/[0-9a-f]{2}/[0-9a-f]{38})$    /git_static/$1 [PT]
-RewriteRule ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.pack)$ /git_static/$1 [PT]
-RewriteRule ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.idx)$  /git_static/$1 [PT]
 ----------------------------------------------------------------