Recognize another error requiring disconnection in the mysql2 adapter
Recognize another error requiring disconnection in the mysql2 adapter

This error doesn't indicate a disconnection, but it indicates the
connection is in an unusable state, so disconnecting it and
removing it from the connection pool is the safer approach.

reubano/sequel,beni55/sequel,mpalmer/sequel,bigfix/sequel,pfarrell/sequel,gferguson-gd/sequel,gferguson-gd/sequel,seeARMS/sequel,uhoh-itsmaciek/sequel,dennis-d/custom_sequel,uhoh-itsmaciek/sequel,seeARMS/sequel,dennis-d/custom_sequel,chef/sequel,mpalmer/sequel,yazshel/sequel,freshpay/sequel,reubano/sequel,davidbegin/sequel,nicohvi/sequel,knut2/sequel,nju520/sequel,nicohvi/sequel,offshore-safety/sequel,davidbegin/sequel,nju520/sequel,offshore-safety/sequel,freshpay/sequel,t-morgan/sequel,pfarrell/sequel,offshore-safety/sequel,Marketcircle/sequel,beni55/sequel,knut2/sequel,t-morgan/sequel,yazshel/sequel