git-svn: rename 'commit' command to 'set-tree'

'set-tree' probably accurately describes what the command
formerly known as 'commit' does.

I'm not entirely sure that 'dcommit' should be renamed to 'commit'
just yet...  Perhaps 'push' or 'push-changes'?

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>

t/t9101-git-svn-props.sh

@@ -74,7 +74,7 @@ test_expect_success "$name" \
 	'git checkout -b mybranch remotes/git-svn &&
 	echo Hi again >> kw.c &&
 	git commit -a -m "test keywoards ignoring" &&
-	git-svn commit remotes/git-svn..mybranch &&
+	git-svn set-tree remotes/git-svn..mybranch &&
 	git pull . remotes/git-svn'
 
 expect='/* $Id$ */'