Changed default release version to 99.9.9

Makefile

@@ -50,7 +50,7 @@ ifeq ($(BUILD_TYPE),debug)
 BUILDFLAGS += -gcflags "-N -l"
 endif
 
-RELEASE_VER := 99.9.9
+RELEASE_VER ?= 99.9.9
 BASE_DIR    := $(shell git rev-parse --show-toplevel)
 GIT_SHA     := $(shell git rev-parse --short HEAD)
 BIN         := $(BASE_DIR)/bin