Merge pull request #1489 from dnephin/faster_integration_tests

Faster integration tests
(cherry picked from commit 5231288b4e)

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>

Conflicts:
	compose/cli/main.py

tests/fixtures/build-ctx/Dockerfile

@@ -1,2 +1,3 @@
 FROM busybox:latest
+LABEL com.docker.compose.test_image=true
 CMD echo "success"

tests/fixtures/dockerfile-with-volume/Dockerfile

@@ -1,3 +1,4 @@
-FROM busybox
+FROM busybox:latest
+LABEL com.docker.compose.test_image=true
 VOLUME /data
 CMD top

tests/fixtures/dockerfile_with_entrypoint/Dockerfile

@@ -1,2 +1,3 @@
 FROM busybox:latest
+LABEL com.docker.compose.test_image=true
 ENTRYPOINT echo "From prebuilt entrypoint"

tests/fixtures/simple-dockerfile/Dockerfile

@@ -1,2 +1,3 @@
 FROM busybox:latest
+LABEL com.docker.compose.test_image=true
 CMD echo "success"