In current implementation, it returns only SZIP_static_FOUND or
SZIP_shared_FOUND.
szip-config.cmake calls check_required_components(SZIP) helper, but
it just set SZIP_FOUND=FALSE when it does not find required componets,
but never set SZIP_FOUND=TRUE.
szip-config.cmake should set SZIP_FOUND=TRUE when it find some
components before calling the helper function.
Signed-off-by: Hiroshi Miura <miurahr@linux.com>