cfdisk: fix typo (undeclared variable since b1f58330)

Signed-off-by: Ruediger Meier <ruediger.meier@ga-group.nl>
Merge branch 'cfdisk-fix-typo' of https://github.com/rudimeier/util-linux

* 'cfdisk-fix-typo' of https://github.com/rudimeier/util-linux:
  cfdisk: fix typo (undeclared variable since b1f58330)