Fix stdin issues with missing config filename ifquery for disable_cli_interfacesfile

Ticket: CM-7066
Reviewed By: roopa
Testing Done: unit tested and wrote new testcase in testifupdown2

Use case for ifquery where stdin used with -i breaks
because interfacesfileiobuf was not checked in addition to interfacesfilename.

Testcase like:

echo '[{"name": "swp1","auto": true,"config": {"address": "10.10.10.10/24"}}]' | ifquery -i - -t json swp1

would fail because while -i was given with stdin, the check for missing filename would produce an error.

It was also decided by consensus that the ifquery command does not need to have a check for
disable_cli_interfacesfile since a query "should" not pose a security check.

(I've also added some test cases for this in cl-tests).

(cherry picked from commit 4d37e932b43da87a9240a866be2d8b9508a9c7eb)

ifupdown/networkinterfaces.py

@@ -434,8 +434,9 @@ class networkInterfaces():
         Assumes networkinterfaces parser object is initialized with the
         parser arguments
         """
-        if self.interfacesfile == None:
-            self.logger.warn('no network interfaces file defined in ifupdown2.conf')
+        if not self.interfacesfile and not self.interfacesfileiobuf:
+            self.logger.warn('no terminal line stdin used or ')
+            self.logger.warn('no network interfaces file defined.')
             return
 
         if self.interfacesfileformat == 'json':