Add TM2 log.Close to log io.Closers
Add TM2 log.Close to log io.Closers

Adds `log.Close` and `log.Closef`, which call `Close` on a given
`io.Closer`, and log any error, along with given context. This allows
succinctly calling `defer log.Close(resp.Body` to log, while retaining
the convenience, brevity, and idiomaticy of `defer`.

hbeatty/incubator-trafficcontrol,weifensh/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,serDrem/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,amiryesh/incubator-trafficcontrol,orifinkelman/incubator-trafficcontrol,weifensh/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,serDrem/incubator-trafficcontrol,knutsel/traffic_control-1,zhilhuan/incubator-trafficcontrol,mdb/incubator-trafficcontrol,serDrem/incubator-trafficcontrol,zhilhuan/incubator-trafficcontrol,rscrimojr/incubator-trafficcontrol,alficles/incubator-trafficcontrol,weifensh/incubator-trafficcontrol,jeffmart/incubator-trafficcontrol,serDrem/incubator-trafficcontrol,serDrem/incubator-trafficcontrol,naamashoresh/incubator-trafficcontrol,naamashoresh/incubator-trafficcontrol,mdb/incubator-trafficcontrol,rscrimojr/incubator-trafficcontrol,jeffmart/incubator-trafficcontrol,amiryesh/incubator-trafficcontrol,rscrimojr/incubator-trafficcontrol,zhilhuan/incubator-trafficcontrol,naamashoresh/incubator-trafficcontrol,amiryesh/incubator-trafficcontrol,mdb/incubator-trafficcontrol,alficles/incubator-trafficcontrol,amiryesh/incubator-trafficcontrol,weifensh/incubator-trafficcontrol,orifinkelman/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,orifinkelman/incubator-trafficcontrol,alficles/incubator-trafficcontrol,zhilhuan/incubator-trafficcontrol,jeffmart/incubator-trafficcontrol,orifinkelman/incubator-trafficcontrol,jeffmart/incubator-trafficcontrol,alficles/incubator-trafficcontrol,alficles/incubator-trafficcontrol,alficles/incubator-trafficcontrol,mdb/incubator-trafficcontrol,mdb/incubator-trafficcontrol,orifinkelman/incubator-trafficcontrol,amiryesh/incubator-trafficcontrol,knutsel/traffic_control-1,naamashoresh/incubator-trafficcontrol,jeffmart/incubator-trafficcontrol,alficles/incubator-trafficcontrol,knutsel/traffic_control-1,knutsel/traffic_control-1,naamashoresh/incubator-trafficcontrol,jeffmart/incubator-trafficcontrol,knutsel/traffic_control-1,weifensh/incubator-trafficcontrol,zhilhuan/incubator-trafficcontrol,amiryesh/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,zhilhuan/incubator-trafficcontrol,knutsel/traffic_control-1,naamashoresh/incubator-trafficcontrol,rscrimojr/incubator-trafficcontrol,rscrimojr/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,orifinkelman/incubator-trafficcontrol,serDrem/incubator-trafficcontrol,amiryesh/incubator-trafficcontrol,rscrimojr/incubator-trafficcontrol,serDrem/incubator-trafficcontrol,alficles/incubator-trafficcontrol,zhilhuan/incubator-trafficcontrol,mdb/incubator-trafficcontrol,weifensh/incubator-trafficcontrol,weifensh/incubator-trafficcontrol,knutsel/traffic_control-1,zhilhuan/incubator-trafficcontrol,serDrem/incubator-trafficcontrol,jeffmart/incubator-trafficcontrol,weifensh/incubator-trafficcontrol,alficles/incubator-trafficcontrol,amiryesh/incubator-trafficcontrol,jeffmart/incubator-trafficcontrol,mdb/incubator-trafficcontrol,knutsel/traffic_control-1,amiryesh/incubator-trafficcontrol,weifensh/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,knutsel/traffic_control-1,serDrem/incubator-trafficcontrol,mdb/incubator-trafficcontrol,naamashoresh/incubator-trafficcontrol,rscrimojr/incubator-trafficcontrol,orifinkelman/incubator-trafficcontrol,hbeatty/incubator-trafficcontrol,orifinkelman/incubator-trafficcontrol,rscrimojr/incubator-trafficcontrol,knutsel/traffic_control-1,orifinkelman/incubator-trafficcontrol,naamashoresh/incubator-trafficcontrol,amiryesh/incubator-trafficcontrol,mdb/incubator-trafficcontrol,zhilhuan/incubator-trafficcontrol,naamashoresh/incubator-trafficcontrol,rscrimojr/incubator-trafficcontrol,weifensh/incubator-trafficcontrol,serDrem/incubator-trafficcontrol,jeffmart/incubator-trafficcontrol,jeffmart/incubator-trafficcontrol,zhilhuan/incubator-trafficcontrol,naamashoresh/incubator-trafficcontrol,alficles/incubator-trafficcontrol,rscrimojr/incubator-trafficcontrol,mdb/incubator-trafficcontrol,orifinkelman/incubator-trafficcontrol