Parametrize BUILD_NAME in /etc/cloud/build.info to make it "minimal-aware".

live-build/auto/build

@@ -409,8 +409,13 @@ deb file:/var/lib/preinstalled-pool/ $LB_DISTRIBUTION $LB_PARENT_ARCHIVE_AREAS
 		fi
 	fi
 	if [ "$PROJECT" = "ubuntu-cpc" ]; then
+        if [ "${SUBPROJECT:-}" = minimized ]; then
+            BUILD_NAME=minimal
+        else
+            BUILD_NAME=server
+        fi
 		cat > chroot/etc/cloud/build.info << EOF
-build_name: server
+build_name: $BUILD_NAME
 serial: $BUILDSTAMP
 EOF
 	fi