BUG: Only register requestion IO COMPONENT modules.

Multiple calls to find_package(ITK COMPONENTS ...) within a project can result
in different IO modules being enabled as ${module}_LOADED.  However, the
${module}_LOADED does not match the requested modules enabled with
COMPONENTS.  Since ITK_LIBRARIES will only contain the requested modules,
we must only use these modules to avoid link errors for the factory
registration symbols.

Change-Id: Ib382ce48fe3f1e9013b09fe6110fe9b060c939c7
Merge topic 'ComponentIO_release'

a0b2c43a BUG: Only register requestion IO COMPONENT modules.