CoverageMapBase.cc: Not restoring ostream format error spotted by Coverity

Original author: rlong

CID 1503022: Not restoring ostream format in dump().

1. format_changed: hex changes the format state of out for category basefield.
   2. format_changed: setfill changes the format state of out for category fill.
 78    out << std::hex << std::setfill('0')
 79        << "Address range: low = " << std::setw(8) << lowAddress
 80        << " high = " << std::setw(8) << highAddress
 81        << std::endl;