Removed deprecated WebRequest::escapeAppendQuery()

This function was deprecated in 1.20 and slated for removal in 1.22;
there were supposed to be warnings given in 1.21 but there does
not seem to be any use of this function otherwise in core.

Change-Id: If70a4e2c1509bf3527d5f8960c14115ce4ab713e
Merge "Removed deprecated WebRequest::escapeAppendQuery()"