Bug 49411: Always use wiki.apiURI for API requests

Debugging output showed a discrepancy between parsoid.apiURI and wiki.apiURI
in some cases. The wiki version is correct in any case, so use that in any
case. This should fix the bug.

We should still investigate why parsoid.apiURI is sometimes not set up
properly.

Change-Id: I495c294a5dbafadac133c0b377b576d297ca529d
Merge "Bug 49411: Always use wiki.apiURI for API requests"