title: `brew link mysql` gives "Error: Could not symlink bin/my_print_defaults"
body: <p><code>brew install mysql-connector-c</code></p>
  
  <p>gave:</p>
  
  <pre><code>Error: Cannot install mysql-connector-c because conflicting formulae are installed.
  
    mysql: because both install MySQL client libraries
  
  Please `brew unlink mysql` before continuing.
  </code></pre>
  
  <p>So:</p>
  
  <pre><code>brew unlink mysql
  Unlinking /usr/local/Cellar/mysql/5.7.9... 88 symlinks removed
  
  brew install mysql-connector-c
  </code></pre>
  
  <p>worked fine. But now <code>brew link mysql</code> gives:</p>
  
  <pre><code>Linking /usr/local/Cellar/mysql/5.7.9... 
  Error: Could not symlink bin/my_print_defaults
  Target /usr/local/bin/my_print_defaults
  is a symlink belonging to mysql-connector-c. You can unlink it:
    brew unlink mysql-connector-c
  
  To force the link and overwrite all conflicting files:
    brew link --overwrite mysql
  
  To list all files that would be deleted:
    brew link --overwrite --dry-run mysql
  </code></pre>
  
  <p>Confused. Unlink? Overwrite?</p>