Patch hostname in configuration file even if name is unsync

Ref https://github.com/GNS3/gns3-gui/issues/1889

gns3server/compute/vpcs/vpcs_vm.py

@@ -171,6 +171,7 @@ class VPCSVM(BaseNode):
         if self.script_file:
             content = self.startup_script
             content = content.replace(self._name, new_name)
+            content = re.sub(r"^set pcname .+$", "set pcname " + new_name, content, flags=re.MULTILINE)
             self.startup_script = content
 
         super(VPCSVM, VPCSVM).name.__set__(self, new_name)