Rollup merge of #3539 - flip1995:travis_osx_fix, r=oli-obk
Rollup merge of #3539 - flip1995:travis_osx_fix, r=oli-obk

Fix rvm/gpg bug in travis osx build

Apparently this workaround isn't needed anymore ([travis](https://travis-ci.org/flip1995/rust-clippy/jobs/467027571)) and fixes the latest osx failures: [travis](https://travis-ci.org/rust-lang/rust-clippy/jobs/467013498#L152)

graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust