The original SVN pluging would mark a folder as dirty if there was an

svn:external set and the output of 'svn status' returned the check for
the external. E.g.

$ svn st
X       Application

Performing status on external item at 'Application'

Shouldn't be marked as being dirty. By grepping for only the valid
output for what should be class as dirty, it won't return false
positives.