mqtt: Check libmosquitto version
mqtt: Check libmosquitto version

Soletta requires libmosquitto >= 1.4.2
Since libmosquitto does not have a pkg-config to check the library
version, it's checking for the version exported in mosquitto.h

Signed-off-by: Flavio Ceolin <979b9165500b0741b9d0500e2efd74fc1547bff7@intel.com>

edersondisouza/soletta,lpereira/soletta,dorileo/soletta,dorileo/soletta,lpereira/soletta,edersondisouza/soletta,lpereira/soletta,lpereira/soletta,dorileo/soletta,edersondisouza/soletta,wzhen12/soletta,lpereira/soletta,dorileo/soletta,edersondisouza/soletta,dorileo/soletta,wzhen12/soletta,dorileo/soletta,edersondisouza/soletta,wzhen12/soletta,edersondisouza/soletta,wzhen12/soletta,wzhen12/soletta,wzhen12/soletta