usb-redir: Adjust pkg-config check for usbredirparser .pc file rename (v2)

The usbredir 0.5 release introduced the new API for 64 bit packet ids, but
it kept the libusbredirparser.pc name as is, meaning that older versions of
qemu will still have their pkg-config check for usbredirparser fulfilled,
and build with the usb-redir device. Due to the API change there will be
some compiler warnings, but the build will succeed, however the usb-redir
device will be broken on 32 bit machines.

To solve this a new usbredir-0.5.2 release is coming, which renames the
libusbredirparser.pc file to libusbredirparser-0.5.pc, so that it will no
longer fulfill the pkg-config check of the qemu-1.2 and older releases,
stopping the (silent) breakage. This patch adjusts qemu master's configure
to properly detect the new usbredir release.

Changes in v2:
-Not only use the new .pc name in the check but also when getting cflags
 and libs!

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
