ha: Don't adopt IKEv1 children when building without IKEv1 support

The adopt_children_job_create() function is not available when IKEv1 support
is disabled. Fixes uncommon builds using --enable-ha --disable-ikev1.

Fixes #690.
Generated new test certificates
credmgr: Fix copy and paste error in add_validator

This won't hurt as long as sets and validators are of the same class.
But as soon as one of the object's class is changed this will cause
either a compile error (best option), or result (most likely) in a
crash.

Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com>
testing: Make strongSwan build recipe more configurable
testing: Add packages to rebuild strongSwan from the repository
testing: Add a script to build the current (or an arbitrary) source tree

WIP: It's unfortunate that the source dir is modified, if we'd limit us to
Git source dirs we could quickly build a tarball via Git and extract that in
the builddir (overwriting existing files to allow incremental builds)
then run autoreconf as we do now.

This allows to (relatively) quickly (re-)build and install the current
or an arbitrary strongSwan source tree within the root image.

As with building the root image in general the guests must not be
running while executing this script.  The guests' images do not have to
be rebuilt, though, as these are automatically rebased to the new root so
no configuration files or other modifications are lost.