[kde-base/pykde4] Raise dev-python/sip and dev-python/PyQt4 dependencies.

The patch added in 4b651f68d3915fd1bc560c51274fdd30c63e6204 to solve bug #517278
is not backwards compatible, so this avoids another build failure if an older
version is installed.

This change can be reviewed if a backwards-compatible version of the patch is
integrated upstream.

Package-Manager: portage-2.2.10