bridge_driver.h: silence gcc warnings:
statement with no effect [-Wunused-value]
unused variable 'net' [-Wunused-variable]

virdrivermoduletest.c: don't require network driver module
if it hasn't been built.

https://www.gnu.org/licenses/gpl-howto.html recommends that
the 'If not, see <url>.' phrase be a separate sentence.

* tests/securityselinuxhelper.c: Remove doubled line.
* tests/securityselinuxtest.c: Likewise.
* globally: s/;  If/.  If/

Based exclusively on work by Eric Blake in a patch posted with the same
subject. However some modifications related to comments and my plans to
add another backend.

Added WITH_INTERFACE as the only automake variable deciding whether to
build the driver and using WITH_NETCF to identify that we're wanting to
use the netcf library as the backend.

* configure.ac: Added with_interface
* src/interface/netcf_driver.c: Renamed..
* src/interface/interface_backend_netcf.c: ..to this to match storage.
* src/interface/netcf_driver.h: Renamed..
* src/interface/interface_driver.h: ..to this.
* daemon/Makefile.am: Respect WITH_INTERFACE and WITH_NETCF.
* libvirt.spec.in: Add RPM support for --with-interface

WITH_INTERFACE is not defined, it should be WITH_NETCF there to load
the interface driver.

Eric posted patch weeks ago to resolve the problems in the whole
build system, but it's not finalised yet:

https://www.redhat.com/archives/libvir-list/2012-June/msg01299.html

I'm going to simply fix the wrong macro name here so that the
interface driver could loaded, and continue the work on the listing
API for interface driver.

Per the FSF address could be changed from time to time, and GNU
recommends the following now: (http://www.gnu.org/licenses/gpl-howto.html)

  You should have received a copy of the GNU General Public License
  along with Foobar.  If not, see <http://www.gnu.org/licenses/>.

This patch removes the explicit FSF address, and uses above instead
(of course, with inserting 'Lesser' before 'General').

Except a bunch of files for security driver, all others are changed
automatically, the copyright for securify files are not complete,
that's why to do it manually:

  src/security/security_selinux.h
  src/security/security_driver.h
  src/security/security_selinux.c
  src/security/security_apparmor.h
  src/security/security_apparmor.c
  src/security/security_driver.c

To ensure all symbols used by loadable driver modules are
exported in libvirt.so, add a test suite that simply loads
each driver in turn

* tests/Makefile.am, tests/virdrivermoduletest.c: Add
  a test case for loading drivers
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>