kas: add GIT_CREDENTIAL_USEHTTPPATH environment variable

This allows the configuration of the git option 'credential.usehttppath' if
the used credential helper requires this.

Signed-off-by: Christoph Freundl <Christoph.Freundl@ifm.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

kas-container

@@ -484,7 +484,8 @@ if [ -n "${KAS_REPO_REF_DIR}" ]; then
 fi
 
 for var in TERM KAS_DISTRO KAS_MACHINE KAS_TARGET KAS_TASK \
-           KAS_PREMIRRORS DISTRO_APT_PREMIRRORS BB_NUMBER_THREADS PARALLEL_MAKE; do
+           KAS_PREMIRRORS DISTRO_APT_PREMIRRORS BB_NUMBER_THREADS PARALLEL_MAKE \
+           GIT_CREDENTIAL_USEHTTPPATH; do
 	if [ -n "$(eval echo \$${var})" ]; then
 		set -- "$@" -e "${var}=$(eval echo \"\$${var}\")"
 	fi