fix lint

Author: Vladimir Kotal

.travis.yml

@@ -52,7 +52,7 @@ jobs:
           skip_cleanup: true
           on:
             condition: $TRAVIS_TAG =~ rc[0-9]+$
-	    branch: master
+            branch: master
         # Full release
         - provider: releases
           api_key:
@@ -61,4 +61,4 @@ jobs:
           skip_cleanup: true
           on:
             condition: ! $TRAVIS_TAG =~ rc[0-9]+$
-	    branch: master
+            branch: master