Downgrade bitflags to build on 1.7

Author: sfackler

.travis.yml

@@ -10,5 +10,6 @@ before_script:
 - "./.travis/setup.sh"
 script:
 - cargo test
+- cargo update -p bitflags --precise 0.5.0
 - cargo test --features "uuid rustc-serialize time unix_socket serde_json chrono openssl bit-vec eui48"
 - (test $TRAVIS_RUST_VERSION != "nightly" || cargo test --features nightly)