Fix gdnative config file set as null
Fix gdnative config file set as null

Fixes #

Setting a GDNativeLibrary config file as null or any other object but a ConfigFile will now cause an error.
honix/godot,vkbsb/godot,BastiaanOlij/godot,firefly2442/godot,godotengine/godot,honix/godot,godotengine/godot,Shockblast/godot,vkbsb/godot,godotengine/godot,akien-mga/godot,pkowal1982/godot,josempans/godot,sanikoyes/godot,firefly2442/godot,Shockblast/godot,Faless/godot,MarianoGnu/godot,guilhermefelipecgs/godot,pkowal1982/godot,Zylann/godot,ZuBsPaCe/godot,firefly2442/godot,firefly2442/godot,ZuBsPaCe/godot,vkbsb/godot,ZuBsPaCe/godot,Faless/godot,vnen/godot,vkbsb/godot,guilhermefelipecgs/godot,MarianoGnu/godot,guilhermefelipecgs/godot,guilhermefelipecgs/godot,BastiaanOlij/godot,BastiaanOlij/godot,Shockblast/godot,Zylann/godot,Faless/godot,guilhermefelipecgs/godot,sanikoyes/godot,MarianoGnu/godot,godotengine/godot,sanikoyes/godot,akien-mga/godot,sanikoyes/godot,DmitriySalnikov/godot,Valentactive/godot,honix/godot,vnen/godot,ZuBsPaCe/godot,sanikoyes/godot,josempans/godot,firefly2442/godot,ZuBsPaCe/godot,honix/godot,pkowal1982/godot,Shockblast/godot,Faless/godot,BastiaanOlij/godot,Shockblast/godot,akien-mga/godot,josempans/godot,pkowal1982/godot,firefly2442/godot,firefly2442/godot,Zylann/godot,MarianoGnu/godot,josempans/godot,vkbsb/godot,guilhermefelipecgs/godot,Zylann/godot,akien-mga/godot,Faless/godot,vnen/godot,vnen/godot,Faless/godot,Zylann/godot,Valentactive/godot,BastiaanOlij/godot,Valentactive/godot,MarianoGnu/godot,MarianoGnu/godot,godotengine/godot,BastiaanOlij/godot,godotengine/godot,josempans/godot,Shockblast/godot,vnen/godot,josempans/godot,sanikoyes/godot,ZuBsPaCe/godot,DmitriySalnikov/godot,guilhermefelipecgs/godot,Valentactive/godot,Zylann/godot,Valentactive/godot,Valentactive/godot,Faless/godot,BastiaanOlij/godot,vkbsb/godot,godotengine/godot,vkbsb/godot,akien-mga/godot,akien-mga/godot,Zylann/godot,sanikoyes/godot,MarianoGnu/godot,firefly2442/godot,vnen/godot,Valentactive/godot,ZuBsPaCe/godot,godotengine/godot,Shockblast/godot,vnen/godot,josempans/godot,DmitriySalnikov/godot,DmitriySalnikov/godot,Valentactive/godot,DmitriySalnikov/godot,honix/godot,vnen/godot,honix/godot,vkbsb/godot,pkowal1982/godot,josempans/godot,ZuBsPaCe/godot,Shockblast/godot,Zylann/godot,Faless/godot,pkowal1982/godot,DmitriySalnikov/godot,akien-mga/godot,sanikoyes/godot,BastiaanOlij/godot,MarianoGnu/godot,pkowal1982/godot,pkowal1982/godot,guilhermefelipecgs/godot,DmitriySalnikov/godot,akien-mga/godot