fix error when open project and close editor
fix error when open project and close editor

### when open project ###
```
ERROR: Attempt to connect nonexistent signal 'size_flags_changed' to method 'queue_sort'
   At: core\object.cpp:1400
ERROR: Attempt to connect nonexistent signal 'minimum_size_changed' to method '_child_minsize_changed'
   At: core\object.cpp:1400
ERROR: Attempt to connect nonexistent signal 'visibility_changed' to method '_child_minsize_changed'
   At: core\object.cpp:1400
```

### when close editor ###
```
ERROR: Nonexistent signal: size_flags_changed
   At: core\object.cpp:1458
ERROR: Nonexistent signal: minimum_size_changed
   At: core\object.cpp:1458
ERROR: Nonexistent signal: visibility_changed
   At: core\object.cpp:1458
```

azurvii/godot,vkbsb/godot,NateWardawg/godot,mcanders/godot,Max-Might/godot,azurvii/godot,ficoos/godot,NateWardawg/godot,pixelpicosean/my-godot-2.1,firefly2442/godot,ficoos/godot,okamstudio/godot,n-pigeon/godot,Paulloz/godot,MrMaidx/godot,JoshuaGrams/godot,azurvii/godot,RandomShaper/godot,MarianoGnu/godot,BastiaanOlij/godot,est31/godot,iap-mutant/godot,RebelliousX/Go_Dot,buckle2000/godot,huziyizero/godot,akien-mga/godot,okamstudio/godot,BastiaanOlij/godot,Zylann/godot,Shockblast/godot,sanikoyes/godot,vnen/godot,opmana/godot,quabug/godot,DmitriySalnikov/godot,gau-veldt/godot,NateWardawg/godot,pixelpicosean/my-godot-2.1,firefly2442/godot,RebelliousX/Go_Dot,Valentactive/godot,Paulloz/godot,MarianoGnu/godot,exabon/godot,tomreyn/godot,guilhermefelipecgs/godot,honix/godot,groud/godot,Paulloz/godot,vnen/godot,jejung/godot,Faless/godot,zicklag/godot,n-pigeon/godot,tomreyn/godot,TheHX/godot,ex/godot,firefly2442/godot,NateWardawg/godot,DmitriySalnikov/godot,Valentactive/godot,Zylann/godot,honix/godot,vnen/godot,Max-Might/godot,Hodes/godot,FateAce/godot,JoshuaGrams/godot,pkowal1982/godot,iap-mutant/godot,n-pigeon/godot,DmitriySalnikov/godot,BastiaanOlij/godot,vnen/godot,firefly2442/godot,buckle2000/godot,honix/godot,Shockblast/godot,honix/godot,Max-Might/godot,sanikoyes/godot,mcanders/godot,rollenrolm/godot,vkbsb/godot,Marqin/godot,Paulloz/godot,est31/godot,godotengine/godot,ficoos/godot,Shockblast/godot,exabon/godot,honix/godot,ageazrael/godot,rollenrolm/godot,RebelliousX/Go_Dot,ficoos/godot,tomreyn/godot,Brickcaster/godot,godotengine/godot,opmana/godot,JoshuaGrams/godot,NateWardawg/godot,MrMaidx/godot,huziyizero/godot,Brickcaster/godot,jejung/godot,Paulloz/godot,RandomShaper/godot,morrow1nd/godot,godotengine/godot,vkbsb/godot,MrMaidx/godot,RandomShaper/godot,NateWardawg/godot,quabug/godot,azurvii/godot,ZuBsPaCe/godot,groud/godot,sanikoyes/godot,iap-mutant/godot,Faless/godot,okamstudio/godot,pixelpicosean/my-godot-2.1,RandomShaper/godot,mcanders/godot,Brickcaster/godot,Faless/godot,Hodes/godot,iap-mutant/godot,ZuBsPaCe/godot,groud/godot,rollenrolm/godot,quabug/godot,akien-mga/godot,jejung/godot,MarianoGnu/godot,okamstudio/godot,sanikoyes/godot,pixelpicosean/my-godot-2.1,guilhermefelipecgs/godot,Marqin/godot,n-pigeon/godot,ZuBsPaCe/godot,morrow1nd/godot,firefly2442/godot,Hodes/godot,mcanders/godot,MarianoGnu/godot,DmitriySalnikov/godot,NateWardawg/godot,ZuBsPaCe/godot,josempans/godot,okamstudio/godot,n-pigeon/godot,ageazrael/godot,NateWardawg/godot,honix/godot,sanikoyes/godot,FateAce/godot,ex/godot,morrow1nd/godot,morrow1nd/godot,jejung/godot,pkowal1982/godot,Faless/godot,RebelliousX/Go_Dot,josempans/godot,guilhermefelipecgs/godot,pkowal1982/godot,azurvii/godot,vkbsb/godot,Shockblast/godot,iap-mutant/godot,gau-veldt/godot,RebelliousX/Go_Dot,JoshuaGrams/godot,jejung/godot,Max-Might/godot,ageazrael/godot,okamstudio/godot,quabug/godot,rollenrolm/godot,JoshuaGrams/godot,FateAce/godot,Zylann/godot,DmitriySalnikov/godot,firefly2442/godot,morrow1nd/godot,okamstudio/godot,vnen/godot,ficoos/godot,Faless/godot,iap-mutant/godot,Marqin/godot,azurvii/godot,josempans/godot,BastiaanOlij/godot,buckle2000/godot,DmitriySalnikov/godot,RebelliousX/Go_Dot,ex/godot,TheHX/godot,josempans/godot,vkbsb/godot,pkowal1982/godot,akien-mga/godot,opmana/godot,MarianoGnu/godot,vkbsb/godot,pkowal1982/godot,zicklag/godot,Valentactive/godot,zicklag/godot,akien-mga/godot,godotengine/godot,Paulloz/godot,sanikoyes/godot,opmana/godot,Faless/godot,quabug/godot,okamstudio/godot,tomreyn/godot,gau-veldt/godot,Shockblast/godot,MarianoGnu/godot,akien-mga/godot,FateAce/godot,huziyizero/godot,quabug/godot,Zylann/godot,BastiaanOlij/godot,ZuBsPaCe/godot,pkowal1982/godot,vnen/godot,guilhermefelipecgs/godot,Zylann/godot,est31/godot,buckle2000/godot,iap-mutant/godot,josempans/godot,quabug/godot,groud/godot,vnen/godot,okamstudio/godot,pkowal1982/godot,MrMaidx/godot,Max-Might/godot,Valentactive/godot,ZuBsPaCe/godot,JoshuaGrams/godot,akien-mga/godot,MarianoGnu/godot,FateAce/godot,quabug/godot,Brickcaster/godot,ficoos/godot,est31/godot,exabon/godot,rollenrolm/godot,huziyizero/godot,guilhermefelipecgs/godot,josempans/godot,Faless/godot,josempans/godot,Shockblast/godot,ageazrael/godot,TheHX/godot,zicklag/godot,sanikoyes/godot,firefly2442/godot,ex/godot,MarianoGnu/godot,opmana/godot,okamstudio/godot,RandomShaper/godot,guilhermefelipecgs/godot,buckle2000/godot,ex/godot,Brickcaster/godot,ex/godot,Hodes/godot,Valentactive/godot,mcanders/godot,NateWardawg/godot,Max-Might/godot,TheHX/godot,godotengine/godot,godotengine/godot,mcanders/godot,zicklag/godot,Shockblast/godot,MrMaidx/godot,Faless/godot,buckle2000/godot,vkbsb/godot,iap-mutant/godot,n-pigeon/godot,ageazrael/godot,vnen/godot,ageazrael/godot,godotengine/godot,Hodes/godot,est31/godot,Paulloz/godot,exabon/godot,akien-mga/godot,FateAce/godot,RandomShaper/godot,TheHX/godot,Brickcaster/godot,exabon/godot,groud/godot,RandomShaper/godot,iap-mutant/godot,quabug/godot,jejung/godot,Shockblast/godot,DmitriySalnikov/godot,iap-mutant/godot,MrMaidx/godot,Valentactive/godot,Zylann/godot,quabug/godot,vkbsb/godot,Zylann/godot,akien-mga/godot,ex/godot,est31/godot,ZuBsPaCe/godot,firefly2442/godot,pixelpicosean/my-godot-2.1,Hodes/godot,groud/godot,Marqin/godot,zicklag/godot,Valentactive/godot,BastiaanOlij/godot,ZuBsPaCe/godot,BastiaanOlij/godot,gau-veldt/godot,ageazrael/godot,exabon/godot,Zylann/godot,BastiaanOlij/godot,morrow1nd/godot,Marqin/godot,huziyizero/godot,n-pigeon/godot,ex/godot,pkowal1982/godot,gau-veldt/godot,godotengine/godot,guilhermefelipecgs/godot,sanikoyes/godot,Marqin/godot,Brickcaster/godot,guilhermefelipecgs/godot,josempans/godot,Valentactive/godot,tomreyn/godot