integration-cli: check err on tmp dir creation

Signed-off-by: Antonio Murdaca <runcom@linux.com>

integration-cli/docker_cli_build_test.go

@@ -4044,6 +4044,7 @@ RUN cat /existing-directory/test/foo | grep Hi
 ADD test.tar /existing-directory-trailing-slash/
 RUN cat /existing-directory-trailing-slash/test/foo | grep Hi`
 		tmpDir, err := ioutil.TempDir("", "fake-context")
+		c.Assert(err, check.IsNil)
 		testTar, err := os.Create(filepath.Join(tmpDir, "test.tar"))
 		if err != nil {
 			c.Fatalf("failed to create test.tar archive: %v", err)
@@ -4089,6 +4090,7 @@ func (s *DockerSuite) TestBuildAddTarXz(c *check.C) {
 			ADD test.tar.xz /
 			RUN cat /test/foo | grep Hi`
 		tmpDir, err := ioutil.TempDir("", "fake-context")
+		c.Assert(err, check.IsNil)
 		testTar, err := os.Create(filepath.Join(tmpDir, "test.tar"))
 		if err != nil {
 			c.Fatalf("failed to create test.tar archive: %v", err)
@@ -4141,6 +4143,7 @@ func (s *DockerSuite) TestBuildAddTarXzGz(c *check.C) {
 			ADD test.tar.xz.gz /
 			RUN ls /test.tar.xz.gz`
 		tmpDir, err := ioutil.TempDir("", "fake-context")
+		c.Assert(err, check.IsNil)
 		testTar, err := os.Create(filepath.Join(tmpDir, "test.tar"))
 		if err != nil {
 			c.Fatalf("failed to create test.tar archive: %v", err)
@@ -4787,9 +4790,7 @@ func (s *DockerSuite) TestBuildSymlinkBreakout(c *check.C) {
 	testRequires(c, DaemonIsLinux)
 	name := "testbuildsymlinkbreakout"
 	tmpdir, err := ioutil.TempDir("", name)
-	if err != nil {
-		c.Fatal(err)
-	}
+	c.Assert(err, check.IsNil)
 	defer os.RemoveAll(tmpdir)
 	ctx := filepath.Join(tmpdir, "context")
 	if err := os.MkdirAll(ctx, 0755); err != nil {
@@ -5143,9 +5144,7 @@ func (s *DockerSuite) TestBuildDockerfileOutsideContext(c *check.C) {
 
 	name := "testbuilddockerfileoutsidecontext"
 	tmpdir, err := ioutil.TempDir("", name)
-	if err != nil {
-		c.Fatal(err)
-	}
+	c.Assert(err, check.IsNil)
 	defer os.RemoveAll(tmpdir)
 	ctx := filepath.Join(tmpdir, "context")
 	if err := os.MkdirAll(ctx, 0755); err != nil {
@@ -5601,9 +5600,7 @@ func (s *DockerTrustSuite) TestTrustedBuildUntrustedTag(c *check.C) {
 func (s *DockerTrustSuite) TestBuildContextDirIsSymlink(c *check.C) {
 	testRequires(c, DaemonIsLinux)
 	tempDir, err := ioutil.TempDir("", "test-build-dir-is-symlink-")
-	if err != nil {
-		c.Fatal(err)
-	}
+	c.Assert(err, check.IsNil)
 	defer os.RemoveAll(tempDir)
 
 	// Make a real context directory in this temp directory with a simple