navigator: usual usleep after poll fail
navigator: usual usleep after poll fail

We don't want to busy loop after the poll fail if that ever happened.

jlecoeur/Firmware,jlecoeur/Firmware,krbeverx/Firmware,PX4/Firmware,Aerotenna/Firmware,dagar/Firmware,krbeverx/Firmware,mcgill-robotics/Firmware,dagar/Firmware,acfloria/Firmware,mcgill-robotics/Firmware,mje-nz/PX4-Firmware,jlecoeur/Firmware,PX4/Firmware,mcgill-robotics/Firmware,jlecoeur/Firmware,dagar/Firmware,PX4/Firmware,PX4/Firmware,Aerotenna/Firmware,krbeverx/Firmware,Aerotenna/Firmware,dagar/Firmware,acfloria/Firmware,dagar/Firmware,mje-nz/PX4-Firmware,dagar/Firmware,mcgill-robotics/Firmware,mje-nz/PX4-Firmware,jlecoeur/Firmware,acfloria/Firmware,Aerotenna/Firmware,mje-nz/PX4-Firmware,acfloria/Firmware,jlecoeur/Firmware,mcgill-robotics/Firmware,mje-nz/PX4-Firmware,krbeverx/Firmware,krbeverx/Firmware,acfloria/Firmware,Aerotenna/Firmware,PX4/Firmware,krbeverx/Firmware,krbeverx/Firmware,PX4/Firmware,mcgill-robotics/Firmware,mcgill-robotics/Firmware,jlecoeur/Firmware,jlecoeur/Firmware,acfloria/Firmware,PX4/Firmware,Aerotenna/Firmware,Aerotenna/Firmware,dagar/Firmware,mje-nz/PX4-Firmware,mje-nz/PX4-Firmware,acfloria/Firmware