mkswap: remove system architecture specific max swap size checks

Since kernel version 2.3.4 (June 1999) all architectures has used
uint32_t as maximum number or pages in a swap device or file, there is no
longer need to support systems earlier than that.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
mkswap: remove unnecessary size check

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
mkswap: use err() rather than perror() && exit()

The messsages in err() are verified from po/util-linux.pot to be already
part of translations.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
mkswap: add struct mkswap_control to remove global variables

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
mkswap: make remaining functions to take control structure as argument

The wipe_device() and new_prober().

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
mkswap: set variable only when it's value is known

Avoid updating ctl->pagesize twice when user does specify page size.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
mkswap: various minor improvement

Use correct data type in page_bad(), and add information to error message
how many bad pages were seen.

In check_blocks() move initialization to variable introduction, fix typo,
and avoid memset() when array initializer can do the job.

In main() use correct initializer for pointer.  Move swap file specific
actions to same location, and add warning when request too --check is
dismissed by command.  At the end remove momory leak.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
docs: fix some wording, grammar and formatting in man page of swapon

Signed-off-by: Benno Schulenberg <bensberg@justemail.net>
swapon: reword some usage strings

Also remove some inconsistent periods and properly punctuate
the closing sentence.

Signed-off-by: Benno Schulenberg <bensberg@justemail.net>