Fix a regression in docker import on error from URL

when the daemon can't download the image from a `docker import` the
error message was lost due to 'err' being redefined with a block by
mistake.  This removes the ":" from "... err := " which fixes it.

Signed-off-by: Doug Davis <dug@us.ibm.com>
Upstream-commit: 3f4926e49b5f6df00ca09328e990729e00cb1a92
Component: engine

components/engine/integration-cli/docker_cli_import_test.go

@@ -39,3 +39,14 @@ func (s *DockerSuite) TestImportDisplay(c *check.C) {
 	}
 
 }
+
+func (s *DockerSuite) TestImportBadURL(c *check.C) {
+	runCmd := exec.Command(dockerBinary, "import", "http://nourl/bad")
+	out, _, err := runCommandWithOutput(runCmd)
+	if err == nil {
+		c.Fatal("import was supposed to fail but didn't")
+	}
+	if !strings.Contains(out, "dial tcp") {
+		c.Fatalf("expected an error msg but didn't get one:\n%s", out)
+	}
+}