Merge #5

5: fix up .travis.yml r=japaric a=japaric



Co-authored-by: Jorge Aparicio <[email protected]>

Author: bors[bot]

.travis.yml

@@ -12,7 +12,7 @@ matrix:
       rust: beta
 
     - env: TARGET=x86_64-unknown-linux-gnu
-      rust:
+      rust: nightly
 
     - env: TARGET=thumbv6m-none-eabi
       rust: nightly