Deprecate usage of git-var -l for getting config vars list

This has been an unfortunate sideway in the git API evolution.
We use git-repo-config for all the other .git/config interaction
so let's also use git-repo-config -l for the variable listing.

Signed-off-by: Petr Baudis <pasky@suse.cz>

Documentation/git-var.txt

@@ -19,7 +19,8 @@ OPTIONS
 -l::
 	Cause the logical variables to be listed. In addition, all the
 	variables of the git configuration file .git/config are listed
-	as well.
+	as well. (However, the configuration variables listing functionality
+	is deprecated in favor of `git-repo-config -l`.)
 
 EXAMPLE
 --------

git-cvsserver.perl

@@ -171,11 +171,11 @@ sub req_Root
        return 0;
     }
 
-    my @gitvars = `git-var -l`;
+    my @gitvars = `git-repo-config -l`;
     if ($?) {
-       print "E problems executing git-var on the server -- this is not a git repository or the PATH is not set correcly.\n";
+       print "E problems executing git-repo-config on the server -- this is not a git repository or the PATH is not set correcly.\n";
         print "E \n";
-        print "error 1 - problem executing git-var\n";
+        print "error 1 - problem executing git-repo-config\n";
        return 0;
     }
     foreach my $line ( @gitvars )