Travis CI: Do not run GDB unless necessary
Travis CI: Do not run GDB unless necessary

AlexHAHA/InertialNav,flyingk/InertialNav,ek99800/InertialNav,vergil1874/InertialNav,flyingk/InertialNav,vergil1874/InertialNav,priseborough/InertialNav,priseborough/InertialNav,zlongshen/InertialNav,priseborough/InertialNav,ek99800/InertialNav,zlongshen/InertialNav,AlexHAHA/InertialNav,priseborough/InertialNav,flyingk/InertialNav,ek99800/InertialNav,AlexHAHA/InertialNav,zlongshen/InertialNav,vergil1874/InertialNav,flyingk/InertialNav