board_status: Use explicit branch name in "git push"

In some configurations, "git push <remote>" (without a branch name)
refuses to do anything.

Change-Id: I23a401b39dd851e9723676586c7f29afa111b49d
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-on: https://review.coreboot.org/14539
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: David Hendricks <dhendrix@chromium.org>

util/board_status/board_status.sh

@@ -383,7 +383,7 @@ if [ $UPLOAD_RESULTS -eq 1 ]; then
 	git add "${vendor}"
 	git commit -a -m "${mainboard_dir}/${tagged_version}/${timestamp}"
 	count=0
-	until git push origin || test $count -eq 3; do
+	until git push origin master || test $count -eq 3; do
 	        git pull --rebase
 		count=$((count + 1))
 	done