Fix phpcs-related scripts

I364b2c2899598f455a548b48725919ad56de09f6 introduced phpcs
to pre-commit but scripts that check for its
setup had a few bugs. Two major changes:

* Don't use PEAR, it's past. Use Composer instead, similarly to npm for
  Node.js dependencies.
* Don't use backquotes in echo messages, they execute the code inside
  them in Bash!

Note: MacOSX users may need to install openssl for this to work
  port install php5-openssl

Change-Id: Ie9bce723b2992b3f7723c106f2c34ffccef44e5d
Merge "Fix phpcs-related scripts"