compat/socket.h: define struct sockaddr_storage if not defined by system headers

This patch defines struct sockaddr_storage and removes conditional compilation
from a number of sites that used this structure conditionally.

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>
Makefile.am: allow unit tests to use crypto functions

This patch adds crypto related libs to TEST_LDADD, which is
libsyslog-ng-crypto.so if that's compiled separately or libsyslog-ng.so.

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>
transport: rename init_method() to init_instance() for consistency

The _method() suffix is commonly used for functions that are assigned to
function pointers pointing to virtual methods. The init_instance() suffix
is used to statically initialize an instance given a self pointer.

So, log_transport_init_method() should have been
log_transport_init_instance().

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>