Move LINK_MASTER/LINK_SLAVE to a new field link_type (purna hit some

issues with having it in flags) + add check for bond slave being already up

Ticket: CM-4408
Reviewed By:
Testing Done: some bond sanity test
(cherry picked from commit 346b62a41fbf4521008cd8a9b0fa227e75a5d994)

ifupdownaddons/iproute2.py

@@ -673,3 +673,15 @@ class iproute2(utilsBase):
 
     def is_bridge(self, bridge):
         return os.path.exists('/sys/class/net/%s/bridge' %bridge)
+
+    def is_link_up(self, ifacename):
+        ret = False
+        try:
+            flags = self.read_file_oneline('/sys/class/net/%s/flags' %ifacename)
+            iflags = int(flags, 16)
+            if (iflags & 0x0001):
+                ret = True
+        except: 
+            ret = False
+            pass
+        return ret