indent: search for !=4 spaces indentation

With this change, dib-lint raises an error if when finding an element
using space indentation that is not multiple of 4.

Co-Authored-By: Jon-Paul Sullivan <jonpaul.sullivan@hp.com>

Change-Id: I470e1fdfc38a3f3c7ba5644c5103f2a9ef073005
Merge "indent: search for !=4 spaces indentation"