ghc-pkg: don't print ignored errors when verbosity=0
ghc-pkg: don't print ignored errors when verbosity=0

Lines like the following are filling up the build logs:

  binary-0.7.5.0: cannot find any of
  ["Data/Binary.hi","Data/Binary.p_hi","Data/Binary.dyn_hi"] (ignoring)

sdiehl/ghc,vTurbine/ghc,nkaretnikov/ghc,ml9951/ghc,GaloisInc/halvm-ghc,ezyang/ghc,mfine/ghc,vikraman/ghc,vikraman/ghc,snoyberg/ghc,nushio3/ghc,siddhanathan/ghc,olsner/ghc,mfine/ghc,shlevy/ghc,da-x/ghc,olsner/ghc,da-x/ghc,gridaphobe/ghc,vTurbine/ghc,siddhanathan/ghc,ml9951/ghc,ml9951/ghc,shlevy/ghc,ghc-android/ghc,elieux/ghc,oldmanmike/ghc,GaloisInc/halvm-ghc,ezyang/ghc,gridaphobe/ghc,vikraman/ghc,wxwxwwxxx/ghc,sdiehl/ghc,AlexanderPankiv/ghc,shlevy/ghc,oldmanmike/ghc,sdiehl/ghc,nushio3/ghc,AlexanderPankiv/ghc,mfine/ghc,da-x/ghc,ghc-android/ghc,snoyberg/ghc,mcschroeder/ghc,elieux/ghc,AlexanderPankiv/ghc,nkaretnikov/ghc,da-x/ghc,ezyang/ghc,mfine/ghc,mettekou/ghc,gridaphobe/ghc,sgillespie/ghc,GaloisInc/halvm-ghc,mettekou/ghc,sgillespie/ghc,sgillespie/ghc,GaloisInc/halvm-ghc,olsner/ghc,sdiehl/ghc,olsner/ghc,ezyang/ghc,tjakway/ghcjvm,nkaretnikov/ghc,ezyang/ghc,snoyberg/ghc,oldmanmike/ghc,ezyang/ghc,tjakway/ghcjvm,AlexanderPankiv/ghc,GaloisInc/halvm-ghc,siddhanathan/ghc,shlevy/ghc,siddhanathan/ghc,snoyberg/ghc,sdiehl/ghc,vikraman/ghc,nkaretnikov/ghc,nushio3/ghc,nushio3/ghc,snoyberg/ghc,sgillespie/ghc,mcschroeder/ghc,GaloisInc/halvm-ghc,siddhanathan/ghc,sgillespie/ghc,vTurbine/ghc,snoyberg/ghc,tjakway/ghcjvm,mfine/ghc,wxwxwwxxx/ghc,nushio3/ghc,mettekou/ghc,wxwxwwxxx/ghc,sdiehl/ghc,oldmanmike/ghc,wxwxwwxxx/ghc,GaloisInc/halvm-ghc,oldmanmike/ghc,AlexanderPankiv/ghc,vikraman/ghc,olsner/ghc,AlexanderPankiv/ghc,shlevy/ghc,ml9951/ghc,mcschroeder/ghc,ml9951/ghc,tjakway/ghcjvm,ghc-android/ghc,AlexanderPankiv/ghc,vTurbine/ghc,mfine/ghc,snoyberg/ghc,nushio3/ghc,tjakway/ghcjvm,oldmanmike/ghc,gridaphobe/ghc,vTurbine/ghc,tjakway/ghcjvm,wxwxwwxxx/ghc,elieux/ghc,vikraman/ghc,elieux/ghc,siddhanathan/ghc,mettekou/ghc,ghc-android/ghc,vTurbine/ghc,mfine/ghc,mcschroeder/ghc,nkaretnikov/ghc,oldmanmike/ghc,mcschroeder/ghc,ghc-android/ghc,nkaretnikov/ghc,gridaphobe/ghc,tjakway/ghcjvm,mettekou/ghc,elieux/ghc,ml9951/ghc,ml9951/ghc,mcschroeder/ghc,nushio3/ghc,da-x/ghc,sdiehl/ghc,gridaphobe/ghc,vTurbine/ghc,ghc-android/ghc,elieux/ghc,sgillespie/ghc,olsner/ghc,shlevy/ghc,mettekou/ghc,vikraman/ghc,shlevy/ghc,ml9951/ghc,elieux/ghc,sgillespie/ghc,wxwxwwxxx/ghc,mcschroeder/ghc,gridaphobe/ghc,mettekou/ghc,olsner/ghc,ezyang/ghc,siddhanathan/ghc,ghc-android/ghc,nkaretnikov/ghc,da-x/ghc,da-x/ghc,wxwxwwxxx/ghc