wireshark: avoid host qtchooser

Some distros provide a 'qtchooser' utility to select Qt library
version. Make sure not to use that host provided utility.

Cc: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>