resolver.cc: fix warnings found by clang-703.0.31 on OS X

resolver.cc: fix warnings found by clang-703.0.31 on OS X

Move try/catch inside the function, as otherwise clang complains:
  cannot refer to a non-static member from the handler of a
  constructor function try block

This also cleans up the initialization of locals[]. Without this,
the code might have ended up closing stdout or another unrelated
socket.