contrib/git-svn: remove the --no-stop-on-copy flag

Output a big warning if somebody actually has a pre-1.0 version
of svn that doesn't support it.

Thanks to Yann Dirson for reminding me it still existed
and attempting to re-enable it :)

I think I subconciously removed support for it earlier...

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/contrib/git-svn/git-svn.perl b/contrib/git-svn/git-svn.perl
index dca4e5c..43b50ec 100755
--- a/contrib/git-svn/git-svn.perl
+++ b/contrib/git-svn/git-svn.perl
@@ -1019,6 +1019,17 @@
 	if (grep /usage: checkout URL\[\@REV\]/,@co_help) {
 		$_svn_co_url_revs = 1;
 	}
+
+	# I really, really hope nobody hits this...
+	unless (grep /stop-on-copy/, (safe_qx(qw(svn log -h)))) {
+		print STDERR <<'';
+W: The installed svn version does not support the --stop-on-copy flag in
+   the log command.
+   Lets hope the directory you're tracking is not a branch or tag
+   and was never moved within the repository...
+
+		$_no_stop_copy = 1;
+	}
 }
 
 # *sigh*, new versions of svn won't honor -r<rev> without URL@<rev>,