Update .travis.yml

Seems like I'd inadvertently created invalid YAML!

.travis.yml

@@ -11,5 +11,4 @@ script:
   - make -C unix
   - cd tests && MICROPY_CPYTHON3=python3.3 ./run-tests
 
-after_failure:
-  - for exp in *.exp; do testbase=$(basename $exp .exp); echo -e "\nFAILURE: $testbase"; diff $testbase.exp $testbase.out; done
+after_failure: for exp in *.exp; do testbase=$(basename $exp .exp); echo -e "\nFAILURE $testbase"; diff $testbase.exp $testbase.out; done