Add the GeoIP include path to the Windows qmake build.

It looks like we need to install and/or configure Qt on the Windows
petri dish builder.

Change-Id: I2bdde7cd9216e311d6402116d6c67b37d37e182d
Reviewed-on: https://code.wireshark.org/review/3997
Reviewed-by: Gerald Combs <gerald@wireshark.org>