coreos-base/coreos-init: add EGIT_BRANCH

As we are using the `git` eclass, we can't simply use a git ref if this
one is on another branch, we need to pass the git branch as well.

Signed-off-by: Mathieu Tortuyaux <[email protected]>
(cherry picked from commit 0ccac12)

Author: tormath1

sdk_container/src/third_party/coreos-overlay/coreos-base/coreos-init/coreos-init-9999.ebuild

@@ -8,6 +8,7 @@ EGIT_REPO_URI="https://github.com/flatcar/init.git"
 if [[ "${PV}" == 9999 ]]; then
 	KEYWORDS="~amd64 ~arm ~arm64 ~x86"
 else
+	EGIT_BRANCH="flatcar-4081-backport"
 	EGIT_COMMIT="d615ae62f1a779bca374855c6e525b2ce064665e" # flatcar-4081-backport
 	KEYWORDS="amd64 arm arm64 x86"
 fi