import missing common class

Change-Id: If1bd345d9de564d3110bac6dfc7e6e775525656c
diff --git a/src/com/mirantis/mk/Aws.groovy b/src/com/mirantis/mk/Aws.groovy
index a17e6f5..e877fff 100644
--- a/src/com/mirantis/mk/Aws.groovy
+++ b/src/com/mirantis/mk/Aws.groovy
@@ -169,6 +169,7 @@
 
 def waitForAutoscalingInstances(venv_path, env_vars, group_name, max_timeout = 600, loop_sleep = 20) {
     def aws = new com.mirantis.mk.Aws()
+    def common = new com.mirantis.mk.Common()
 
     timeout(time: max_timeout, unit: 'SECONDS') {
         withEnv(env_vars) {