Add support for missing baseimageless mode in tfw.sh

hack/tfw.sh

@@ -26,6 +26,7 @@ run_frontend()
 
 release_baseimage()
 {
+    [ ! -d "$BASEIMAGE_PATH" ] && return || :
     cd $BASEIMAGE_PATH
     TAG="$(baseimage_releasename)"
     read -p "Tag and push new TFW version \"${TAG}\"? [y/N]" -r && echo
@@ -38,6 +39,7 @@ release_baseimage()
 
 build_baseimage()
 {
+    [ ! -d "$BASEIMAGE_PATH" ] && return || :
     cd $BASEIMAGE_PATH
     docker build -t "${BASEIMAGE_NAME}:$(baseimage_releasename)" -t "${BASEIMAGE_NAME}:latest" .
 }