search/cve: exclude unsupported images from fixed-tag list.

If image vulnerability scan does not support any media type, considering those images as an infected image and now this images will not be shown in fixed images list.

Fixes issue #130

pkg/cli/BUILD.bazel

@@ -39,7 +39,7 @@ go_test(
         "image_cmd_test.go",
         "root_test.go",
     ],
-      data = [
+    data = [
         "//:exported_testdata",
     ],
     embed = [":go_default_library"],

pkg/cli/cve_cmd_test.go

@@ -425,7 +425,7 @@ func TestServerCVEResponse(t *testing.T) {
 			str := space.ReplaceAllString(buff.String(), " ")
 			str = strings.TrimSpace(str)
 			So(err, ShouldBeNil)
-			So(str, ShouldEqual, "")
+			So(strings.TrimSpace(str), ShouldContainSubstring, "IMAGE NAME TAG DIGEST SIZE")
 		})
 
 		Convey("invalid image", func() {