Make an int64->double conversion explicit to silence -Wconversion.
Make an int64->double conversion explicit to silence -Wconversion.

Addresses issue #173:
  https://code.google.com/p/googlemock/issues/detail?id=173

marcossilvadecastro/googletest,amitkr/googletest,marcossilvadecastro/googletest,amitkr/googletest,amitkr/googletest,marcossilvadecastro/googletest,marcossilvadecastro/googletest