Update "podman diff container and image with same name" e2e test

Update the "podman diff container and image with same name" e2e test to
not expect a built image to include /etc, since newer buildah won't
include an item in a layer if it was only created in a rootfs in order
to have something mounted onto it while processing a RUN instruction.
A few exceptions are still made for the sake of conformance tests.

Signed-off-by: Nalin Dahyabhai <[email protected]>

Author: nalind

test/e2e/diff_test.go

@@ -150,13 +150,13 @@ RUN touch %s`, ALPINE, imagefile)
 		session = podmanTest.Podman([]string{"diff", name})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(HaveLen(2))
+		Expect(session.OutputToStringArray()).To(HaveLen(1))
 		Expect(session.OutputToString()).To(ContainSubstring(imagefile))
 
 		session = podmanTest.Podman([]string{"image", "diff", name})
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
-		Expect(session.OutputToStringArray()).To(HaveLen(2))
+		Expect(session.OutputToStringArray()).To(HaveLen(1))
 		Expect(session.OutputToString()).To(ContainSubstring(imagefile))
 
 		// container diff has to show the container