docs: distribute more coding convention documentation

These files may be useful for anyone making modifications to
source files in a tarball distribution.

* src/Makefile.am (EXTRA_DIST): Add THREADS.txt.
* daemon/Makefile.am (EXTRA_DIST): Add THREADING.txt.

daemon/Makefile.am

@@ -29,6 +29,7 @@ EXTRA_DIST =						\
 	libvirtd.lxc.logrotate.in                       \
 	libvirtd.uml.logrotate.in                       \
 	test_libvirtd.aug                               \
+	THREADING.txt					\
 	$(AVAHI_SOURCES)				\
 	$(DAEMON_SOURCES)
 

src/Makefile.am

@@ -610,7 +610,8 @@ augeas_DATA += qemu/libvirtd_qemu.aug
 augeastest_DATA += qemu/test_libvirtd_qemu.aug
 
 endif
-EXTRA_DIST += qemu/qemu.conf qemu/libvirtd_qemu.aug qemu/test_libvirtd_qemu.aug
+EXTRA_DIST += qemu/qemu.conf qemu/libvirtd_qemu.aug \
+		qemu/test_libvirtd_qemu.aug qemu/THREADS.txt
 
 
 if WITH_LXC