UBUNTU: [debian] add rebuild-test support for autopkgtest

Add support for the DEB_BUILD_OPTIONS rebuild-test which indicates this is
not a full build but a quick smoke test.  For us short circuit the build
and only make the first flavour on the assumption it is representative
of the others.

BugLink: http://bugs.launchpad.net/bugs/1081500Signed-off-by: Andy Whitcroft <apw@canonical.com>

debian/rules

@@ -41,6 +41,12 @@ ifeq ($(DEB_BUILD_PROFILE),bootstrap)
     do_flavour_header_package=false
 endif
 
+# autopkgtest -- rebuild support
+#  only build the first flavour on the assumption it is representative
+ifeq ($(DEB_BUILD_PROFILE),autopkgtest)
+flavours := $(firstword $(flavours))
+endif
+
 # Debian Build System targets
 binary: binary-indep binary-arch