Time and check nearly all file system action commands (#754684)

There has been an undocumented rule that external commands displayed in
the operation details, as part of file system manipulations, only get a
time and check mark displayed when multiple commands are needed, and not
otherwise.  (GParted checks whether all commands are successful or not
regardless of whether a check mark is displayed in the operation details
or not).

EXCEPTION 1: btrfs resize

Since the following commit [1] from 2013-02-22, GParted stopped
displaying the timing for the btrfs resize command in the operation
details.  It being part of a multi-command sequence to perform the step.
This is because FileSystem::execute_command() since the commit can only
check the exit status for zero / non-zero while timing and checking the
command status but btrfs resize needs to consider some non-zero statuses
as successful.

[1] 52a2a9b0
    Reduce threading (#685740)

EXCEPTION 2: ext2/3/4 move and copy using e2image

When use of e2image was added [2] the single command steps were timed
and check.

[2] 86111fe1
    Use e2image to move/copy ext[234] file systems (#721516)

EXCEPTION 3: fat16/32 write label and UUID

Uses Utils::execute_command() rather than FileSystem::execute_command()
so can be separately changed.  See the following commit for resolution
of the final commands not yet timed and check mark displayed.

CHANGE:

Lets make a simpler rule of always displaying the time and a check mark
for all external commands displayed in the operation details.  However
this makes several of the other single command actions need special exit
status handling because zero success, non-zero failure is not correct
for every case.  Specifically affects resizing of reiserfs and check
repair of ext2/3/4, fat16/32, jfs and reiserfs.

After this change all external commands run as file system actions must
follow one of these two patterns of using the EXEC_CHECK_STATUS flag or
separately calling FileSystem::set_status() to register success or
failure of the command:
    exit_status = execute_command(cmd, od, EXEC_CHECK_STATUS...);
or:
    exit_status = execute_command(cmd, od, ...);
    bool success = (exit_status == 0 || exit_status == OTHER_SUCCESS_VALUE...);
    set_status(od, success );

Bug 754684 - Updates to FileSystem:: and Utils::execute_command()
             functions