make: disable itest error whitelist check

Since we don't really do anything with the errors we check in the itest
error whitelist but get a lot of failed Travis runs because of it, we
disable the check for the moment.

docs/release-notes/release-notes-0.14.0.md

@@ -33,6 +33,8 @@ you.
 
 * [A new build target itest-race](https://github.com/lightningnetwork/lnd/pull/5542) 
   to help uncover undetected data races with our itests.
+* [The itest error whitelist check was removed to reduce the number of failed
+  Travis builds](https://github.com/lightningnetwork/lnd/pull/5588).
 
 # Documentation