Bug 61492

Description of Problem:


        #include <netdb.h>

        int main(int argc, char **argv )
        {
                write(1,"A\n",2);
                getservbyname(argv[1],0);
                write(1,"B\n",2);
                return 0;
        }

If I run this with an undefined service name (such as "quack"), I see glibc
trying to close an fd it shouldn't be:

        close(3)                       = 0
        close(3)                       = 0
        A
        close(3)                       = 0
        close(3)                       = 0        close(3)                       = 0
        close(3)                       = 0
        close(3)                       = 0
        close(3)                       = 0
        close(3)                       = 0
        close(3)                       = 0
        close(4)                       = 0
        close(3)                       = 0
        close(4)                       = -1 EBADF (Bad file descriptor)
        close(3)                       = 0
        B

Note, this also happens if nis/nisplus is used before files for service lookups,
and whether a valid service name is used or not. 

If files are checked first, and the lookup succeeds the excess close does not
happen. 

In a multithreaded application the potential exists for reassignment of the fd
before the second (erroneous) close.