core: remove pyenv in Travis CI

.travis.yml

@@ -22,8 +22,8 @@ matrix:
         env: BUILDTOOL="cmake" BUILDARGS="-DENABLE_CODE_COVERAGE=ON" CODECOVERAGE="1"
 
 before_script:
-    # Workaround https://github.com/travis-ci/travis-ci/issues/5326
-    - export PATH=$(echo $PATH | tr ':' "\n" | sed '/\/opt\/python/d' | tr "\n" ":" | sed "s|::|:|g")
+    - rm -rf "$HOME/.pyenv"
+    - sudo rm -rf /opt/pyenv
     - echo 'APT::Install-Recommends "false";' | sudo tee -a /etc/apt/apt.conf
     - travis_retry sudo apt-get update -qq
     - travis_retry sudo apt-get -y install devscripts equivs python-pip libenchant-dev autopoint cmake lcov pkg-config libncursesw5-dev gem2deb libperl-dev python-dev python3-dev libaspell-dev liblua5.3-dev tcl8.6-dev guile-2.0-dev libv8-dev libcurl4-gnutls-dev libgcrypt20-dev libgnutls-dev zlib1g-dev curl libcpputest-dev php7.0-dev libphp7.0-embed