Bug 9357: Missing 'c' option in MARC21 LEADER_18 value builder

Bug 9357: Missing 'c' option in MARC21 LEADER_18 value builder

This patch adds option 'c' to the position 18
of the leader value builder.
Also corrects label for option 'i'

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Elliott Davis <elliott@bywatersolions.com>
Works as described
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>