Support fetching classic gadget trees from a non-github-mirrored launchpad repo.

debian/changelog

@@ -1,3 +1,10 @@
+livecd-rootfs (2.622) UNRELEASED; urgency=medium
+
+  * Support fetching classic gadget trees from a non-github-mirrored launchpad
+    repository for ubuntu-image to use.
+
+ -- Łukasz 'sil2100' Zemczak <lukasz.zemczak@ubuntu.com>  Wed, 30 Oct 2019 14:06:48 +0100
+
 livecd-rootfs (2.621) focal; urgency=medium
 
   * Make sure the imx6 subarch uses the ubuntu-image imageformat.

live-build/auto/config

@@ -389,7 +389,10 @@ case $IMAGEFORMAT in
 			UBUNTU_IMAGE_ARGS="$UBUNTU_IMAGE_ARGS${PROPOSED:+ --with-proposed}"
 			UBUNTU_IMAGE_ARGS="$UBUNTU_IMAGE_ARGS${EXTRA_PPAS:+ --extra-ppas \"$EXTRA_PPAS\"}"
 
-			git clone git://git.launchpad.net/~canonical-foundations/snap-$MODEL/+git/github-mirror -b classic config/$PREFIX-gadget
+			# We need to look in two places for the gadget tree:
+			# - Launchpad hosted gadgets will be in the snap-gadget repo
+			# - Github hosted gadgets are mirrored into a github-mirror repo
+			git clone git://git.launchpad.net/~canonical-foundations/snap-$MODEL/+git/snap-$MODEL -b classic config/$PREFIX-gadget || git clone git://git.launchpad.net/~canonical-foundations/snap-$MODEL/+git/github-mirror -b classic config/$PREFIX-gadget
 
 			echo "IMAGEFORMAT=$IMAGEFORMAT" >> config/common
 			echo "SUITE=$SUITE" >> config/common