Remove redundant match for mountpoints

Summary:
m_excludeList is populated from m_settings->excludeFolders(), so one of
the checks is redundant.

Remove the first and not the second one, as the first does not use
normalized pathes and may miss some matches.

Reviewers: #baloo, ngraham, davidedmundson

Reviewed By: #baloo, ngraham

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D27636