gitconfig/rebase.sh: adapt default branch name

Whatever it is, it likely won't be cros/chromeos-2013.04 anymore.

Change-Id: I020b65a7406e3bef7d1c8fad8c530354b1f78819
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/11438
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Tested-by: build bot (Jenkins)
diff --git a/util/gitconfig/rebase.sh b/util/gitconfig/rebase.sh
index 4bc32a4..26cec55 100755
--- a/util/gitconfig/rebase.sh
+++ b/util/gitconfig/rebase.sh
@@ -13,7 +13,7 @@
 #
 
 # Adapt to your remote branch:
-BRANCH="cros/chromeos-2013.04"
+BRANCH="cros/chromeos-2015.07"
 
 # When pulling in patches from another tree from a gerrit repository,
 # do the following at the end of a larger cherry-pick series: