Fix ks-controller panic due to missing nil checking in mutli-branch pipeline

Signed-off-by: rick <rick@jenkins-zh.cn>

pkg/simple/client/devops/jenkins/internal/common_test.go

@@ -0,0 +1,14 @@
+package internal
+
+import "testing"
+
+func TestCommonSituation(t *testing.T) {
+	// make sure these functions do not panic
+	// I add these test cases because it's possible that users just do give the git source
+	AppendGitlabSourceToEtree(nil, nil)
+	AppendGithubSourceToEtree(nil, nil)
+	AppendBitbucketServerSourceToEtree(nil, nil)
+	AppendGitSourceToEtree(nil, nil)
+	AppendSingleSvnSourceToEtree(nil, nil)
+	AppendSvnSourceToEtree(nil, nil)
+}