Allow to wipe workspace before cloning for gitSSHCheckout for Mirantis package

Patch I0a1c8491584b7e50140b738303bad9240fd7f347 missed this change for
main lib package, so let's add it, because basic 'vars' functions will
be removed.

Change-Id: Ic1dec6bd48ca82d87a730e85b4730d25cbcafa8f
diff --git a/src/com/mirantis/mcp/Git.groovy b/src/com/mirantis/mcp/Git.groovy
index 4bf2056..7281a04 100644
--- a/src/com/mirantis/mcp/Git.groovy
+++ b/src/com/mirantis/mcp/Git.groovy
@@ -65,6 +65,7 @@
   body()
 
   def merge = config.withMerge ?: false
+  def wipe = config.withWipeOut ?: false
   def targetDir = config.targetDir ?: "./"
   def port = config.port ?: "29418"
 
@@ -79,6 +80,11 @@
     scmExtensions.add([$class: 'LocalBranch', localBranch: "${config.branch}"])
   }
 
+  // we need wipe workspace before checkout
+  if (wipe) {
+    scmExtensions.add([$class: 'WipeWorkspace'])
+  }
+
   checkout(
     scm: [
       $class: 'GitSCM',