[SEBA-304] Enable fields to be set to empty string, so that synchronizer can null them out

Change-Id: Ie3b8dffb0ad8b89a4cd1b034feabc72ed99ebb2e
diff --git a/VERSION b/VERSION
index af0b7dd..238d6e8 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.0.6
+1.0.7
diff --git a/xos/synchronizer/models/models.py b/xos/synchronizer/models/models.py
index 2fc2993..9713ab4 100644
--- a/xos/synchronizer/models/models.py
+++ b/xos/synchronizer/models/models.py
@@ -89,12 +89,12 @@
             self.creator = self.caller
 
         # validate MAC Address
-        if hasattr(self, 'mac_address') and self.mac_address is not None:
+        if hasattr(self, 'mac_address') and self.mac_address:
             if not re.match("[0-9a-f]{2}([-:]?)[0-9a-f]{2}(\\1[0-9a-f]{2}){4}$", self.mac_address.lower()):
                 raise XOSValidationError("The MAC address specified is not valid: %s" % self.mac_address)
 
         # validate c_tag
-        if hasattr(self, 'c_tag') and self.c_tag is not None:
+        if hasattr(self, 'c_tag') and self.c_tag:
             is_update_with_same_tag = False
 
             if not self.is_new:
@@ -107,10 +107,10 @@
             if self.c_tag in self.get_used_c_tags() and not is_update_with_same_tag:
                 raise XOSValidationError("The c_tag you specified (%s) has already been used on device %s" % (self.c_tag, self.onu_device))
 
-        if not hasattr(self, "c_tag") or self.c_tag is None:
+        if not hasattr(self, "c_tag") or not self.c_tag:
             self.c_tag = self.generate_c_tag()
 
-        if not hasattr(self, "s_tag") or self.s_tag is None:
+        if not hasattr(self, "s_tag") or not self.s_tag:
             self.s_tag = self.generate_s_tag()
 
         self.set_owner()