Some fstab files only have 3 fields and mount options are completely omitted.

Empty labels are not allowed anymore.
One can reset them with -r flag but that is not supported in older
dosfstools. So for now we just manually set label to NO_LABEL.

BUG: 432941

As the sfdisk man page says on the option '--wipe' that
specifies whether or not to wipe signatures in order
to avoid collisions:

> When this option is not given, the default is auto,
> in which case signatures are wiped only when in interactive mode

but sfdisk is not run in interactive mode here, since
stdin does not refer to a terminal, and the sfdisk
man page says:

> It [i.e. sfdisk] runs in interactive mode if executed on terminal
> (stdin refers to a terminal).

Therefore, explicitly pass the '--wipe=always' option to
sfdisk so that old signatures are wiped when a new partition
table is created.

Bug: 431628

BUG: 429191

Bug: 430907

Add some diagrams explaining difference between
source/targetOffsets and read/writeOffset.

Simply returning failure should be sufficient.

Move include of BLKID_INCLUDE_DIRS into scope it is used.
UUID_INCLUDE_DIRS is unused, left over from before partitionmanager
switched away from libuuid in 26e7f9d7ef .
Explicit Qt5Core_INCLUDE_DIRS no longer needed.
src/ is automatically available for kpmcore target, also exposed in
its build link interface.

That one uses std::is_constructible<impl, QObject *, const QVariantList &>
which will fail for our current plugin constructors due to being private
and with only friend class KPluginFactory.

If the name of the mount point contains spaces or tabs these
can be escaped as `\040' and '\011' respectively.

BUG: 428932

Old version QString::SplitBehavious is now deprecated.

BUG: 412887

We need this to avoid multiple authentication requests when applying
long operations.

Otherwise, the user will have to authenticate after each job,
which can mean up to 4 password dialogs for some longer operations.