tools: move libxenctrl below tools/libs

Today tools/libxc needs to be built after tools/libs as libxenctrl is
depending on some libraries in tools/libs. This in turn blocks moving
other libraries depending on libxenctrl below tools/libs.

So carve out libxenctrl from tools/libxc and move it into
tools/libs/ctrl.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> (stubdom parts)
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> (python parts)
Acked-by: Wei Liu <wl@xen.org>

tools/python/Makefile

@@ -33,7 +33,7 @@ uninstall:
 
 .PHONY: test
 test:
-	LD_LIBRARY_PATH=$$(readlink -f ../libxc):$$(readlink -f ../xenstore) $(PYTHON) -m unittest discover
+	LD_LIBRARY_PATH=$$(readlink -f ../libs/ctrl):$$(readlink -f ../xenstore) $(PYTHON) -m unittest discover
 
 .PHONY: clean
 clean: