Changed C++ style comment to C style for 'sql/net_serv.cc' which will be symlinked
to 'libmysql/net.c'.
sql/net_serv.cc:
Even though this is (by name) a C++ file, it is later symlinked to 'libmysql/net.c'
and so the source will be treated as plain C: No C++ comments in here!