g13: New option --no-mount.

* g13/g13.c (oNoMount): New.
(opts): Add --no-mount.
(main): Implement this.
* g13/g13-common.h (opt): Add field no_mount.
* common/status.h (STATUS_PLAINDEV): New.
* g13/sh-cmd.c (has_option): Uncomment.
(cmd_mount): Add option --no-mount and pass down.
* g13/sh-dmcrypt.c (sh_dmcrypt_mount_container): Add arg nomount and
emit PLAINDEV status line.
(sh_dmcrypt_umount_container): Rund findmnt before umount.
--

This option can be used to decrypt a device but not to mount it.  For
example to run fsck first.  A command or option to run fsck before a
mount will eventually be added.

The use of findmnt is needed so that we can easily remove a device
which has not been mounted.

g13/g13.c

@@ -103,6 +103,7 @@ enum cmd_and_opt_values {
   oWithColons,
   oDryRun,
   oNoDetach,
+  oNoMount,
 
   oNoRandomSeedFile,
   oFakedSystemTime
@@ -137,6 +138,7 @@ static gpgrt_opt_t opts[] = {
   ARGPARSE_s_s (oLogFile, "log-file",  N_("|FILE|write log output to FILE")),
   ARGPARSE_s_n (oNoLogFile, "no-log-file", "@"),
   ARGPARSE_s_i (oLoggerFD, "logger-fd", "@"),
+  ARGPARSE_s_n (oNoMount, "no-mount", N_("stop right before running mount")),
 
   ARGPARSE_s_n (oDryRun, "dry-run", N_("do not make any changes")),
 
@@ -518,6 +520,8 @@ main (int argc, char **argv)
 
         case oNoDetach: /*nodetach = 1; */break;
 
+        case oNoMount: opt.no_mount = 1; break;
+
         case oDebug:
           if (parse_debug_flag (pargs.r.ret_str, &opt.debug, debug_flags))
             {