Allow to wipe workspace before cloning

Change-Id: I0a1c8491584b7e50140b738303bad9240fd7f347
diff --git a/vars/gitSSHCheckout.groovy b/vars/gitSSHCheckout.groovy
index 46b76bc..cf6e0e4 100644
--- a/vars/gitSSHCheckout.groovy
+++ b/vars/gitSSHCheckout.groovy
@@ -6,6 +6,7 @@
   body()
 
   def merge = config.withMerge ?: false
+  def wipe = config.withWipeOut ?: false
   def targetDir = config.targetDir ?: "./"
   def port = config.port ?: "29418"
 
@@ -19,6 +20,10 @@
   if (merge) {
     scmExtensions.add([$class: 'LocalBranch', localBranch: "${config.branch}"])
   }
+  // we need wipe workspace before checkout
+  if (wipe) {
+    scmExtensions.add([$class: 'WipeWorkspace'])
+  }
 
   checkout(
     scm: [