Increase sleep time for start_thread spec
Increase sleep time for start_thread spec

Travis sometimes takes a bit longer, this should make the build more
stable.

appsignal/appsignal,matrinox/appsignal-ruby,matrinox/appsignal-ruby,subvisual/appsignal,stijnster/appsignal-ruby,q-m/appsignal,appsignal/appsignal,appsignal/appsignal-ruby,appsignal/appsignal-ruby,rranelli/appsignal,codefarmdev/haystack,appsignal/appsignal-ruby,stijnster/appsignal-ruby,appsignal/appsignal-ruby,stijnster/appsignal-ruby,matrinox/appsignal-ruby