Merge rust-lang#923

923: Don't build the bors-ng staging.tmp branch on travis r=carols10cents

i'm going to merge this myself with bors-ng to test, eees wafer thin

Author: bors-voyager[bot]

.travis.yml

@@ -2,6 +2,10 @@ language: rust
 sudo: false
 dist: trusty
 
+branches:
+  except:
+  - staging.tmp
+
 cache:
   cargo: true