update conformance test output

Change-Id: Iee2e61c394ec04419871c60b0c510c735d5e9618
diff --git a/src/com/mirantis/mk/Test.groovy b/src/com/mirantis/mk/Test.groovy
index 6807756..4ef8b10 100644
--- a/src/com/mirantis/mk/Test.groovy
+++ b/src/com/mirantis/mk/Test.groovy
@@ -16,7 +16,7 @@
     def salt = new com.mirantis.mk.Salt()
     def outfile = "/tmp/" + image.replaceAll('/', '-') + '.output'
     salt.runSaltProcessStep(master, 'ctl01*', 'cmd.run', ["docker run --rm --net=host -e API_SERVER=${k8s_api} ${image} > ${outfile}"])
-    print("Conformance test output saved in ${outfile}")
+    print("Conformance test output saved in " + outfile)
 }
 
 /**