GUACAMOLE-1241: Build against Debian repository that has non-snapshot version of FreeRDP.

Debian stable currently provides a FreeRDP package that is a snapshot of
commit 2693389a103394e035edc2a01055ca2c9ccccb21, whereas
stable-backports provides a FreeRDP package from release 2.2.0. Only a
release or release candidate can be relied upon for consistent behavior.
1 file changed