git svn: find-rev allows short switches for near matches

Allow -B and -A to act as short aliases for --before and --after
options respectively.  This reduces typing and hopefully allows
reuse of muscle memory for grep(1) users.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
diff --git a/git-svn.perl b/git-svn.perl
index 40565cd..97ff562 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -260,8 +260,8 @@
 			} ],
 	'find-rev' => [ \&cmd_find_rev,
 	                "Translate between SVN revision numbers and tree-ish",
-			{ 'before' => \$_before,
-			  'after' => \$_after } ],
+			{ 'B|before' => \$_before,
+			  'A|after' => \$_after } ],
 	'rebase' => [ \&cmd_rebase, "Fetch and rebase your working directory",
 			{ 'merge|m|M' => \$_merge,
 			  'verbose|v' => \$_verbose,