Add ability to run cookiecutter tests with extra repo passed

Run cookiecutter tests with ability to override extra repo, for
example, during testing reclass package from review.

Change-Id: I6adaa3b2d46b33c0c8e831b2f65221003868b8f2
diff --git a/test-cookiecutter-reclass-chunk.groovy b/test-cookiecutter-reclass-chunk.groovy
index b1266a3..cdc6e1e 100644
--- a/test-cookiecutter-reclass-chunk.groovy
+++ b/test-cookiecutter-reclass-chunk.groovy
@@ -34,6 +34,10 @@
                     'dockerContainerName': extraVars.DockerCName,
                     'testContext': extraVars.modelFile
                 ]
+                if (extraVars.useExtraRepos) {
+                    config['extraRepos'] = extraVars.extraRepos ? extraVars.extraRepos : [:]
+                    config['extraRepoMergeStrategy'] = extraVars.extraRepoMergeStrategy ? extraVars.extraRepoMergeStrategy : ''
+                }
                 saltModelTesting.testNode(config)
             } catch (Throwable e) {
                 // If there was an error or exception thrown, the build failed