Reverted build

Author: Simon Hofmann

.travis.yml

@@ -36,7 +36,9 @@ env:
     TAG=3.4.3-contrib
 
 before_install:
-  - chmod +x ./ci/$BUILD_TASK/$BUILD_TASK.sh
+  - if [[ $BUILD_TASK != "prebuild" ]]; then
+    chmod +x ./ci/$BUILD_TASK/$BUILD_TASK.sh
+    fi
 
 install: travis_wait 30 docker pull justadudewhohacks/opencv4nodejs-ci:$TAG