Workaround travis brekage

See: https://github.com/travis-ci/travis-ci/issues/5145

.travis.yml

@@ -9,13 +9,15 @@ before_install:
   - go get github.com/mattn/goveralls
 
 script:
-    - go test github.com/v2ray/v2ray-core/...
-    - ./testing/coverage/coverall
+  - go test github.com/v2ray/v2ray-core/...
+  - ./testing/coverage/coverall
 
 env:
   secure: "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"
 
-before_deploy: "./release/release.sh"
+before_deploy:
+  - rvm 1.9.3 do gem install mime-types -v 2.6.2
+  - "./release/release.sh"
 
 deploy:
   provider: releases