Try just upgrading wget

.travis.yml

@@ -91,7 +91,7 @@ before_install:
     - export PATH=$(echo $PATH | tr ':' "\n" | sed '/\/opt\/python/d' | tr "\n" ":" | sed "s|::|:|g")
     # Install the non-python dependencies: fftw, libav, eigen
     - if [[ $TRAVIS_OS_NAME == "linux" ]]; then sudo -H apt-get -qq update; sudo -H apt-get install -y python-dev libfftw3-dev libav-tools libeigen3-dev; fi
-    - if [[ $TRAVIS_OS_NAME == "osx" ]]; then brew update; brew install fftw libav eigen wget; brew cask install gfortran; brew upgrade; fi
+    - if [[ $TRAVIS_OS_NAME == "osx" ]]; then brew update; brew install fftw libav eigen wget; brew cask install gfortran; brew upgrade wget; fi
 
     # List current contents of directories that should be being cached.
     - ls -l $HOME