merge-kernel: Gerrit namespace support

New optional argument "-N <namespace>" to specifiy the merge branch
prefix (Gerrit namespace). Default to 'stable-merge/linux' for Linux stable
release merges (merges against a release tag) or 'merge' for all other
merges.

BUG=b:183621345
TEST=Use script

Change-Id: Id59456c156146ea465087a4426e608861bb8b138
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/2785649
Reviewed-by: William K Lin <wklin@google.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Commit-Queue: Guenter Roeck <groeck@chromium.org>
Tested-by: Guenter Roeck <groeck@chromium.org>
1 file changed