Clean more build utils in integration cli

- Remove deprecated buildImage* functions
- Rename buildImageNew to buildImage
- Use *check.C in fakeContext* setup and in getIdByName

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

integration-cli/docker_cli_push_test.go

@@ -161,14 +161,13 @@ func testConcurrentPush(c *check.C) {
 	repos := []string{}
 	for _, tag := range []string{"push1", "push2", "push3"} {
 		repo := fmt.Sprintf("%v:%v", repoName, tag)
-		_, err := buildImage(repo, fmt.Sprintf(`
+		buildImageSuccessfully(c, repo, withDockerfile(fmt.Sprintf(`
 	FROM busybox
 	ENTRYPOINT ["/bin/echo"]
 	ENV FOO foo
 	ENV BAR bar
 	CMD echo %s
-`, repo), true)
-		c.Assert(err, checker.IsNil)
+`, repo)))
 		repos = append(repos, repo)
 	}