contrib/git-svn: make sure our git-svn is up-to-date for test

Bugs like the last one could've been avoided if it weren't for
this...
Signed-off-by: NEric Wong <normalperson@yhbt.net>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

contrib/git-svn/Makefile

@@ -28,7 +28,7 @@ git-svn.xml : git-svn.txt
 git-svn.html : git-svn.txt
 	asciidoc -b xhtml11 -d manpage \
 		-f ../../Documentation/asciidoc.conf $<
-test:
+test: git-svn
 	cd t && $(SHELL) ./t0000-contrib-git-svn.sh
 
 clean: