PropertyList extension: print filenames as part of errors.
PropertyList extension: print filenames as part of errors.

This includes the filename in I/O errors, so users no longer receive
errors like "no such file or directory" without actually seeing the
path of the file in question.

Change-Id: Ie296e315ad6e2753535d53469bee13c0d803f12c
Reviewed-by: Christian Kandeler <3aa99dcdd3f0cac61fb81c2a11771c0cc2497607@theqtcompany.com>

qt-labs/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qt-labs/qbs,qt-labs/qbs,qt-labs/qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qtproject/qt-labs-qbs