QRegExp includes can be found in several files where there's not even a
use of the class. This patch aims to avoid needless includes as well as
follow the "include only what you use" moto.
This patch removes a QRegExp include from the QStringList header which
means that there is likely going to be code breaking since QStringList
is used in many places and would get QRegExp in.
[ChangeLog][Potentially Source-Incompatible Changes] qstringlist.h no
longer includes qregexp.h.
Change-Id: I32847532f16e419d4cb735ddc11a26551127e923
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>