Install Ansible via pip instead of Homebrew

When installed via Homebrew, it seemed not possible to make molecule
work correctly. So instead we install both ansible and molecule via pip,
and everything works.

Brewfile

@@ -15,7 +15,6 @@ tap 'homebrew/cask-versions'
 #
 
 brew 'ack'
-brew 'ansible'
 brew 'aspell'
 brew 'bash'
 brew 'bazaar'
@@ -42,7 +41,6 @@ brew 'node'
 brew 'peco'
 brew 'pgformatter'
 brew 'postgresql'
-brew 'pyenv'
 brew 'rbenv'
 brew 'rclone'
 brew 'readline'