remove no-longer-necessary homebrew git modifications

Author: tkelman

.travis.yml

@@ -61,7 +61,6 @@ before_install:
         brew install -v jq bar;
         contrib/travis_fastfail.sh || exit 1;
         brew tap staticfloat/julia;
-        (cd $(brew --prefix)/Library/Taps/staticfloat/homebrew-julia && git fetch origin +refs/heads/*:refs/remotes/origin/* && git checkout origin/staging);
         brew rm --force $(brew deps --HEAD julia);
         brew install -v --only-dependencies --HEAD julia;
         BUILDOPTS="-j3 USECLANG=1 LLVM_CONFIG=$(brew --prefix llvm37-julia)/bin/llvm-config-3.7.1 VERBOSE=1 USE_BLAS64=0 SUITESPARSE_INC=-I$(brew --prefix suite-sparse-julia)/include FORCE_ASSERTIONS=1 STAGE2_DEPS=utf8proc";