Fix xapi xm-tests.

There were a couple of small bugs in the xapi xm-test:
o outdated XenAPI calls were removed from testcase
  (02_xapi-vbd_basic)
o minor problem with XendLocalStorageRepository
  is fixed (missed list_images() function - which
  is moved from the XenQCoWStroageRepo to the common
  base class XendStorageRepository)
  which was detected running 02_xapi-vbd_basic.
o XenAPI session handling and connecting is fixed.
o 03_xapi-network_pos was rewritten and now uses
  XenAPI.

Signed-off-by: Andreas Florath <xen@flonatel.org>

tools/python/xen/xend/XendQCoWStorageRepo.py

@@ -260,18 +260,6 @@ class XendQCoWStorageRepo(XendStorageRepository):
         
         return False
 
-    def list_images(self):
-        """ List all the available images by UUID.
-
-        @rtype: list of strings.
-        @return: list of UUIDs
-        """
-        self.lock.acquire()
-        try:
-            return self.images.keys()
-        finally:
-            self.lock.release()
-
     def free_space_bytes(self):
         """Returns the amount of available space in KB.
         @rtype: int

tools/python/xen/xend/XendStorageRepository.py

@@ -103,3 +103,16 @@ class XendStorageRepository:
 
     def destroy_vdi(self, vdi_struct):
         raise NotImplementedError()
+
+    def list_images(self):
+        """ List all the available images by UUID.
+
+        @rtype: list of strings.
+        @return: list of UUIDs
+        """
+        self.lock.acquire()
+        try:
+            return self.images.keys()
+        finally:
+            self.lock.release()
+