devel/plasma: Fix BUILD_DEPENDS after 2619476372c0

• The recently updated devel/py-capstone, which is used as RUN_DEPENDS pulls in devel/capstone which leads to conflicting dependendies with devel/capstone4 which is installed prior during the build phase.
  
  Fix the issue by switching the BUILD_DEPENDS to devel/capstone.

• Bump PORTREVISION due changed package contents as the shared libs are created from the more recent devel/capstone.

Reported by: pkg-fallout