Don't use the QRegExp methods that modify the object [QtCore]

Don't use the QRegExp methods that modify the object [QtCore]

QRegExp matching methods modify the object, which we don't want to. In
particular, when we receive a QRegExp from the user or we store in a
context that might require thread-safety, make sure we make a copy
before using it.

QRegularExpression has no such shortcoming.

Task-number: QTBUG-25064
Change-Id: Icf22986cd5f6fd086518c78a7d56e6cadfe9f5f6
Reviewed-by: Giuseppe D'Angelo <dangelog@gmail.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>