strongswan: update verion to 5.1.1

* Add a patch to fix the function parameter.
* Add PACKAGECONFIG for optional packages instead of explicitly
  disable, and set sqlite and curl as default.
* Remove the split package strongswan-plugins.
* Add configure option --without-lib-prefix so it doesn't
  search for libraries in includedir and libdir to avoid QA error.

Signed-off-by: Jackie Huang <jackie.huang@windriver.com>
Signed-off-by: Joe MacDonald <joe@deserted.net>