serf: fix possible deadlock
serf: fix possible deadlock

samaitra/serf,gnawhleinad/serf,hashicorp/serf,patrickviet/serf,dalehamel/serf,dalehamel/serf,mapuri/serf,gnawhleinad/serf,mbrukman/serf,patrickviet/serf,curtiszimmerman/serf,yonglehou/serf,curtiszimmerman/serf,hashicorp/serf,curtiszimmerman/serf,hashicorp/serf,patrickviet/serf,pmenglund/serf,yonglehou/serf,FollowMyDev/serf,samaitra/serf,hashicorp/serf,yonglehou/serf,FollowMyDev/serf,patrickviet/serf,minhkiller/serf,jmptrader/serf,FollowMyDev/serf,minhkiller/serf,yonglehou/serf,mbrukman/serf,dalehamel/serf,jmptrader/serf,gnawhleinad/serf,dalehamel/serf,mbrukman/serf,minhkiller/serf,mbrukman/serf,patrickviet/serf,FollowMyDev/serf,dalehamel/serf,samaitra/serf,mapuri/serf,FollowMyDev/serf,minhkiller/serf,samaitra/serf,gnawhleinad/serf,jmptrader/serf,mapuri/serf,yonglehou/serf,curtiszimmerman/serf,FollowMyDev/serf,samaitra/serf,dalehamel/serf,pmenglund/serf,pmenglund/serf,curtiszimmerman/serf,mapuri/serf,mbrukman/serf,pmenglund/serf,mapuri/serf,mbrukman/serf,hashicorp/serf,gnawhleinad/serf,patrickviet/serf,minhkiller/serf,jmptrader/serf,curtiszimmerman/serf,gnawhleinad/serf,minhkiller/serf,jmptrader/serf,jmptrader/serf,samaitra/serf,mapuri/serf,yonglehou/serf,pmenglund/serf,pmenglund/serf