Fix qt5 plugin paths

Do not pollute qt5 paths with the plugins prefix. An alternative
solution would be using qt.conf file.
Status Job ID Name Coverage
  External
passed cdash

pending cmb@master-junction-osx-shared-release+superbuild
failed cmb@master-kerbin-windows-shared-release+superbuild

failed cmb@master-moho-linux-shared-relwithdebinfo+python3+superbuild

failed cmb@master-moho-linux-shared-relwithdebinfo+superbuild

pending cmb@master-norkit-osx-shared-release+superbuild
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pending cmb@master-talosiv-osx-shared-release+superbuild
failed cmb@master-tatooine-osx-shared-release+superbuild

passed ghostflow-branch-check-master

pending smtk@master-junction-osx-shared-release+superbuild
passed smtk@master-kerbin-windows-shared-release+superbuild

failed smtk@master-moho-linux-shared-relwithdebinfo+python3+superbuild

passed smtk@master-moho-linux-shared-relwithdebinfo+superbuild

failed smtk@master-moho-linux-shared-relwithdebinfo+superbuild+vtk

pending smtk@master-norkit-osx-shared-release+superbuild
pending smtk@master-praxis-windows-shared-release+superbuild
pending smtk@master-talosiv-osx-shared-release+superbuild
passed smtk@master-tatooine-osx-shared-release+superbuild

failed cmb@master-kerbin-windows-shared-release+superbuild

00:30:18

failed cmb@master-moho-linux-shared-relwithdebinfo+python3+superbuild

00:48:02

failed cmb@master-moho-linux-shared-relwithdebinfo+python3+superbuild

failed cmb@master-moho-linux-shared-relwithdebinfo+python3+superbuild

failed cmb@master-moho-linux-shared-relwithdebinfo+superbuild

00:47:49

failed cmb@master-moho-linux-shared-relwithdebinfo+superbuild

failed cmb@master-moho-linux-shared-relwithdebinfo+superbuild

failed cmb@master-tatooine-osx-shared-release+superbuild

01:13:19

failed cmb@master-tatooine-osx-shared-release+superbuild

failed cmb@master-tatooine-osx-shared-release+superbuild

passed smtk@master-kerbin-windows-shared-release+superbuild

01:17:36

failed smtk@master-kerbin-windows-shared-release+superbuild

failed smtk@master-kerbin-windows-shared-release+superbuild

failed smtk@master-kerbin-windows-shared-release+superbuild

failed smtk@master-kerbin-windows-shared-release+superbuild

00:52:43

passed smtk@master-kerbin-windows-shared-release+superbuild

passed smtk@master-kerbin-windows-shared-release+superbuild

failed smtk@master-moho-linux-shared-relwithdebinfo+python3+superbuild

failed smtk@master-moho-linux-shared-relwithdebinfo+python3+superbuild

00:36:51

failed smtk@master-moho-linux-shared-relwithdebinfo+python3+superbuild

passed smtk@master-moho-linux-shared-relwithdebinfo+superbuild

passed smtk@master-moho-linux-shared-relwithdebinfo+superbuild

passed smtk@master-moho-linux-shared-relwithdebinfo+superbuild

00:38:03

failed smtk@master-moho-linux-shared-relwithdebinfo+superbuild+vtk

failed smtk@master-moho-linux-shared-relwithdebinfo+superbuild+vtk

failed smtk@master-moho-linux-shared-relwithdebinfo+superbuild+vtk

00:00:11

passed smtk@master-tatooine-osx-shared-release+superbuild

passed smtk@master-tatooine-osx-shared-release+superbuild

passed smtk@master-tatooine-osx-shared-release+superbuild

00:55:59