Changeset 9a4d250 in mod_gnutls for test/test-18_client_verification_wrong_cert.bash

Avoid external make calls for test environment setup

All targets needed to set up the test suite environment are now
directly handled by the makefile created through automake, avoiding
any external make calls. The rules for X.509 and PGP certificate
management are included from the old test makefile through automake.

Note that those included rules use syntax that automake warns is GNU
make specific and might not work with other make implementations. This
is not a regression, just increased visibility, so automake
portability warnings are ignored.