Disable recursive watchdog signal handler
Disable recursive watchdog signal handler

If we are in the signal handler, we don't want to handle
the signal again.  In extreme cases, this can cause a stack overflow
and segfault Redis.

Fixes #1771

LittlePeng/redis,hanmichael/redis,upsoft/redis,jqk6/redis,shanegxxiao/redis,sidsen/redis,sidsen/redis,liqiang199105/redis,liqiang199105/redis,nandhanurrevanth/redis,alpha8/redis,ScottKaiGu/redis,kolonse/redis,miminus/redis,ideaar/redis,jacklee0810/redis,quangnguyen90/redis,sidsen/redis,LittlePeng/redis,ideaar/redis,miminus/redis,quangnguyen90/redis,liqiang199105/redis,laurencee/redis,miminus/redis,adamweixuan/redis,jaambee/redis,StartTheShift/redis-shift,jaambee/redis,nandhanurrevanth/redis,quangnguyen90/redis,jacklee0810/redis,alpha8/redis,Jonavin/redis,erwin00776/redis-2.8-optimize,laurencee/redis,janeasystems/redis,liqiang199105/redis,kolonse/redis,liqiang199105/redis,damy/redis,janeasystems/redis,jaambee/redis,LittlePeng/redis,jacklee0810/redis,damy/redis,quangnguyen90/redis,damy/redis,hanmichael/redis,Jonavin/redis,jaambee/redis,fanxu/redis,laurencee/redis,StartTheShift/redis-shift,nandhanurrevanth/redis,enginekit/redis,janeasystems/redis,ScottKaiGu/redis,Cybermaxs/redis,quangnguyen90/redis,janeasystems/redis,enginekit/redis,hanmichael/redis,upsoft/redis,shanegxxiao/redis,ScottKaiGu/redis,jqk6/redis,miminus/redis,enginekit/redis,alpha8/redis,jqk6/redis,Cybermaxs/redis,kolonse/redis,kolonse/redis,ideaar/redis,upsoft/redis,enginekit/redis,Cybermaxs/redis,nandhanurrevanth/redis,jaambee/redis,Cybermaxs/redis,erwin00776/redis-2.8-optimize,adamweixuan/redis,jacklee0810/redis,fanxu/redis,kolonse/redis,ideaar/redis,damy/redis,upsoft/redis,enginekit/redis,kts12345/redis,hanmichael/redis,Cybermaxs/redis,janeasystems/redis,jacklee0810/redis,sidsen/redis,shanegxxiao/redis,kts12345/redis,Jonavin/redis,jqk6/redis,laurencee/redis,kts12345/redis,ScottKaiGu/redis,shanegxxiao/redis,ideaar/redis,sidsen/redis,hanmichael/redis,kts12345/redis,sidsen/redis,damy/redis,adamweixuan/redis,miminus/redis,erwin00776/redis-2.8-optimize,fanxu/redis,upsoft/redis,alpha8/redis,alpha8/redis,Jonavin/redis,fanxu/redis,Jonavin/redis,shanegxxiao/redis,adamweixuan/redis,jqk6/redis,StartTheShift/redis-shift,nandhanurrevanth/redis,kts12345/redis,adamweixuan/redis,laurencee/redis,ScottKaiGu/redis,erwin00776/redis-2.8-optimize