Revert "build-sys: gettexts 0.18 -> 0.18.2 due to MKDIR_P"

This reverts commit 0576dbd3ea114dc35b797ad7216f1ed5814e7c6b.

There is two possible ways:

 1/ autotools complains that gettext 0.18 uses deprecated macro
 2/ users complain that 0.18.2 is too new and they cannot rebuild

We care about users and project contributors, so let's live for the
next util-linux release with the old stupid gettext 0.18.

Signed-off-by: Karel Zak <kzak@redhat.com>