This is needed for TextField control for instance.
If QT_NO_CLIPBOARD is defined, canPaste will always return false.
Fixes dialogs auto test when QT_NO_CLIPBOARD is defined.

[ChangeLog][QtQuick][Platform Specific Changes] Added canPaste
property to TextInput element also on platforms that don't support
a clipboard (QT_NO_CLIPBOARD is defined).

Change-Id: Ia85205672ba59c1fce70852458c514b03d332de6
Reviewed-by: Alan Alpert <aalpert@blackberry.com>