Corrected an error in the initialization of the gps position, init only if we have a fix
Corrected an error in the initialization of the gps position, init only if we have a fix

lis-epfl/MAVRIC_Library,lis-epfl/MAVRIC_Library,gburri/MAVRIC_Library,lis-epfl/MAVRIC_Library,gburri/MAVRIC_Library,gburri/MAVRIC_Library