fix save -copy when there are no dependencies
fix save -copy when there are no dependencies

Don't assume that directories Godeps and Godeps/_workspace
will be created by copySrc. If there is no source to copy,
that won't happen.

michaeltrobinson/godep,vincentcr/godep,gorcz/godep,brandur/godep,triggit/godep-legacy,jonboulle/godep,beni55/godep,kinvolk/godep,dpatel06/godep,fredr/godep,buddhamagnet/godep,Scalingo/godep,glasser/godep,ncdc/godep,tshr/godep,hamfist/deppy,msn217/godep,AndBicScadMedia/godep,thorning/godep,ofer43211/godep,pshevtsov/godep,ReachingOut/godep,soundtrackyourbrand/godep,njohns-grovo/godep,mapix/godep,snowsnail/godep,fkautz/godep,wfxiang08/godep,takecy/godep,hellosuper/godep,SDkie/godep