qgis2-ltr:fix Qt4 plugin installs; define QT_PLUGIN_PATH for multi-paths
qgis2-ltr:fix Qt4 plugin installs; define QT_PLUGIN_PATH for multi-paths

[ci skip]

OSGeo/homebrew-osgeo4mac,OSGeo/homebrew-osgeo4mac,OSGeo/homebrew-osgeo4mac