sbin/hammer: Use printf() instead of fprintf(stdout)

sbin/hammer: Use printf() instead of fprintf(stdout)

Follow sbin/hammer's coding style (as well as C in general).

 # grep "fprintf(stdout" sbin/hammer -riI
 sbin/hammer/cmd_info.c:                                         fprintf(stdout, "\n");
 sbin/hammer/cmd_info.c:                         fprintf(stdout, "No mounted HAMMER filesystems found\n");
 sbin/hammer/cmd_info.c:                 fprintf(stdout, "No mounted filesystems found\n");
 sbin/hammer/cmd_info.c: fprintf(stdout, "Volume identification\n");
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tLabel               %s\n", fip->vol_name);
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tNo. Volumes         %d\n", fip->nvolumes);
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tHAMMER Volumes      ");
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tRoot Volume         %s\n", rootvol);
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tFSID                %s\n", fsid);
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tHAMMER Version      %d\n", fip->version);
 sbin/hammer/cmd_info.c: fprintf(stdout, "Big-block information\n");
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tTotal      %10jd\n", (intmax_t)fip->bigblocks);
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tUsed       %10jd (%.2lf%%)\n"
 sbin/hammer/cmd_info.c: fprintf(stdout, "Space information\n");
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tNo. Inodes %10jd\n", (intmax_t)fip->inodes);
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tTotal size     %6s (%jd bytes)\n",
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tUsed           %6s (%.2lf%%)\n", buf,
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tReserved       %6s (%.2lf%%)\n", buf,
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tFree           %6s (%.2lf%%)\n", buf,
 sbin/hammer/cmd_info.c: fprintf(stdout, "PFS information\n");
 sbin/hammer/cmd_info.c: fprintf(stdout, "\tPFS ID  Mode    Snaps  Mounted on\n");
 sbin/hammer/cmd_info.c:         fprintf(stdout, "\t%6d  %-6s",
 sbin/hammer/cmd_info.c:         fprintf(stdout, " %6s  ", (pi->head.error && pi->snapcount == 0) ? "-" : buf);
 sbin/hammer/cmd_info.c:                 fprintf(stdout, "%s", pi->mountedon);
 sbin/hammer/cmd_info.c:                 fprintf(stdout, "not mounted");
 sbin/hammer/cmd_info.c:         fprintf(stdout, "\n");