remote: Don't reject remote polkit if client lacks support

remote: Don't reject remote polkit if client lacks support

If you compile a client --without-polkit, and connect to a URI that needs
polkit auth, the connection will fail with:

$ ./tools/virsh --connect qemu+ssh://crobinso@machine/system
error: failed to connect to the hypervisor
error: authentication failed: unsupported authentication type 2

This is because the client side portion of the polkit handling is
compiled out. However, nothing polkit specific is actually required
of the client.

Fix that error by unconditionally compiling the basic polkit client
handling.

https://bugzilla.redhat.com/show_bug.cgi?id=635529