Fixing Fatal log for sTag and makefile custom docker properties

Change-Id: Ibe3111d330713c381ded6ba97f2b164fe08f7d07
diff --git a/Makefile b/Makefile
index 08808f2..390b43b 100644
--- a/Makefile
+++ b/Makefile
@@ -19,9 +19,9 @@
 
 ## Docker related
 DOCKER_TAG  			?= ${VERSION}
-DOCKER_REPOSITORY  		?= ""
-DOCKER_REGISTRY 		?= ""
-DOCKER_RUN_ARGS			?= ""
+DOCKER_REPOSITORY  		?=
+DOCKER_REGISTRY 		?=
+DOCKER_RUN_ARGS			?=
 DOCKER_PORTS			?= -p 50070:50070 -p 50060:50060 -p 50071:50071 -p 50072:50072 -p 50073:50073 -p 50074:50074 -p 50075:50075
 TYPE                            ?= minimal