Add libmoosex-method-signatures-perl to Build-Depends

Supposed to address:

| Indirect call of method "method" on a block at /tmp/buildd/ngcp-schema-1.002+0~20130702123451.12+wheezy~1.gbpc374da/blib/lib/NGCP/Schema/Config.pm line 11.

Thanks, Lars

debian/control

@@ -14,6 +14,7 @@ Build-Depends: debhelper (>= 8),
                libgtk2-gladexml-simple-perl,
                liblog-log4perl-perl,
                libmoosex-fileattribute-perl,
+               libmoosex-method-signatures-perl,
                libmoosex-nonmoose-perl,
                libmoosex-singleton-perl,
                libparse-debianchangelog-perl,