Increase the timeout for the inttest/proto_gpb
Increase the timeout for the inttest/proto_gpb

On my slow old netbook with a 1.6GHz CPU, this inttest
takes about 40 seconds to run, of which network activity
is about 3s, the default timeout of retest is 30s.
Add a generous margin to avoid unnecessary timeouts.

macintux/rebar,RubberCthulhu/rebar,K2InformaticsGmbH/rebar,CMoH/rebar,cloudant/couchdb-rebar,norton/rebar,bsmr-erlang/rebar,lpgauth/rebar,SiDen/rebar,oubiwann/rebar,bsmr-erlang/rebar,lrascao/rebar,K2InformaticsGmbH/rebar,lrascao/rebar,choptastic/rebar,matwey/rebar,rebar/rebar,csyangchen/rebar,csyangchen/rebar,lrascao/rebar,csyangchen/rebar,GabrielNicolasAvellaneda/rebar,choptastic/rebar,dcarastan/rebar,matwey/rebar,matwey/rebar,K2InformaticsGmbH/rebar,macintux/rebar,jacktang/rebar,norton/rebar,beni55/rebar,macintux/rebar,norton/rebar,paulo-ferraz-oliveira/rebar,apache/couchdb-rebar,lpgauth/rebar,CMoH/rebar,beni55/rebar,shkumagai/rebar,matwey/rebar,SiDen/rebar,apache/couchdb-rebar,lrascao/rebar,cloudant/couchdb-rebar,rebar/rebar,matwey/rebar,platinumthinker/rebar,evnix/rebar,CMoH/rebar,norton/rebar,dcarastan/rebar,K2InformaticsGmbH/rebar,oubiwann/rebar,RubberCthulhu/rebar,shkumagai/rebar,dcarastan/rebar,scatterbrain/rebar,paulo-ferraz-oliveira/rebar,beni55/rebar,SiDen/rebar,jacktang/rebar,scatterbrain/rebar,paulo-ferraz-oliveira/rebar,shkumagai/rebar,platinumthinker/rebar,GabrielNicolasAvellaneda/rebar,cloudant/couchdb-rebar,bsmr-erlang/rebar,apache/couchdb-rebar,choptastic/rebar,GabrielNicolasAvellaneda/rebar,jacktang/rebar,platinumthinker/rebar,lrascao/rebar,scatterbrain/rebar,evnix/rebar,lpgauth/rebar,K2InformaticsGmbH/rebar,rebar/rebar,bsmr-erlang/rebar,oubiwann/rebar,evnix/rebar