add fix missing common in setSaltOverrides

Change-Id: Iaab1e30bee17c1b349711e355ea19d81647972e5
diff --git a/src/com/mirantis/mk/Salt.groovy b/src/com/mirantis/mk/Salt.groovy
index 31158b2..2fdc0b3 100644
--- a/src/com/mirantis/mk/Salt.groovy
+++ b/src/com/mirantis/mk/Salt.groovy
@@ -439,6 +439,7 @@
 
 def setSaltOverrides(master, salt_overrides, debug=false) {
     def mcpcommon = new com.mirantis.mcp.Common()
+    def common = new com.mirantis.mk.Common()
 
     def salt_overrides_map = mcpcommon.loadYAML(salt_overrides)
     for (entry in common.entries(SALT_OVERRIDES_MAP)) {