The removal of plugin cache in qt5 (8ed47d961d)
means that only the original loading error (from QElfParser) is reported.
In Qt4 this was previously two different strings depending on if the library
had been previously cached.
Task-number: QTBUG-22834
Change-Id: I15a4adc7d0f8f23f16bb2aa8ba8b968db770f074
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>