Update helper script for 5.0.0-rc1
Update helper script for 5.0.0-rc1

The pending release of Qt5 is getting closer. We're at first release
candidate now.

There's something quite unexpected: QtWebKit has not been tagged for
-rc1; either beta2 == rc1, or the tag is just late. I can't believe the
module would have been dropped from essentials.

bostik/qt5-specs,bostik/qt5-specs