travis-ci only run make check within docker (#4854)
travis-ci only run make check within docker (#4854)

 * otherwise the build environment doesn't get the proper return code
dagar/Firmware,Aerotenna/Firmware,krbeverx/Firmware,PX4/Firmware,mcgill-robotics/Firmware,dagar/Firmware,darknight-007/Firmware,mje-nz/PX4-Firmware,jlecoeur/Firmware,mje-nz/PX4-Firmware,acfloria/Firmware,krbeverx/Firmware,Aerotenna/Firmware,jlecoeur/Firmware,jlecoeur/Firmware,mcgill-robotics/Firmware,dagar/Firmware,Aerotenna/Firmware,mje-nz/PX4-Firmware,Aerotenna/Firmware,krbeverx/Firmware,mje-nz/PX4-Firmware,Aerotenna/Firmware,darknight-007/Firmware,krbeverx/Firmware,acfloria/Firmware,dagar/Firmware,mcgill-robotics/Firmware,Aerotenna/Firmware,mcgill-robotics/Firmware,acfloria/Firmware,darknight-007/Firmware,PX4/Firmware,jlecoeur/Firmware,acfloria/Firmware,krbeverx/Firmware,PX4/Firmware,jlecoeur/Firmware,PX4/Firmware,PX4/Firmware,mje-nz/PX4-Firmware,mje-nz/PX4-Firmware,dagar/Firmware,mje-nz/PX4-Firmware,PX4/Firmware,PX4/Firmware,dagar/Firmware,jlecoeur/Firmware,mcgill-robotics/Firmware,Aerotenna/Firmware,mcgill-robotics/Firmware,jlecoeur/Firmware,krbeverx/Firmware,darknight-007/Firmware,acfloria/Firmware,darknight-007/Firmware,dagar/Firmware,mcgill-robotics/Firmware,jlecoeur/Firmware,acfloria/Firmware,krbeverx/Firmware,acfloria/Firmware