UBUNTU: [Debian] make rebuild use skippable error codes when skipping.

BugLink: https://bugs.launchpad.net/bugs/1823056Signed-off-by: Dimitri John Ledkov <xnox@ubuntu.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

debian/tests/control

 Tests: rebuild
 Depends: @builddeps@, fakeroot
-Restrictions: allow-stderr
+Restrictions: allow-stderr, skippable
 
 Tests: ubuntu-regression-suite
 Depends: build-essential, gcc-multilib [amd64 arm64 armhf i386 powerpc], gdb, git, bzr

debian/tests/rebuild

@@ -13,7 +13,7 @@ do
 done
 if [ "$build_needed" -eq 0 ]; then
 	echo "rebuild: short circuiting build for '${ADT_TEST_TRIGGERS}'"
-	exit 0
+	exit 77
 fi
 
 set -e