Revert "Captive portal: rotate fallback urls"

After discussion in the cl we agreed to use "|" as a separator. However  String.split() input arg is a regex and not a literal string, so that "|" will actually split the urls characters per characters.

Will revert and resubmit with a comma.

This reverts commit 0908daaa.

Change-Id: Ifab25e41bec806fbc1d2c13ffd81d4ad91598c89