web: model: Allow unsetting IP address/hostname

src/rouse/web/model.py

@@ -61,6 +61,9 @@ class Host(Base, Serializable):
 
     @ipaddr.setter
     def ipaddr(self, value):
+        if not value:
+            self._ipaddr = None
+            return
         if ':' in value:
             af = socket.AF_INET6
         else:
@@ -77,6 +80,9 @@ class Host(Base, Serializable):
 
     @hostname.setter
     def hostname(self, value):
+        if not value:
+            self._hostname = None
+            return
         if not self.HOSTNAME_RE.match(value):
             raise ValueError('Invalid hostname: {}'.format(value))
         self._hostname = value