security/f-prot: Unbreak after e3847f7b2db96e8de279767e427f3c66c0743982

With LICENSE=f-prot and LICENSE_TEXT set the framework creates
${WRKDIR}/f-prot however WRKSRC=${WRKDIR}/f-prot too. Rename the
license to fix this.

/bin/sh: cannot create /wrkdirs/usr/ports/security/f-prot/work/f-prot: Is a directory