Remove a bit of useless $wgCapitalLinks logic, all these code paths lead through...

Remove a bit of useless $wgCapitalLinks logic, all these code paths lead through Title::secureAndSpit() which handles initial-character-capitalization.
*In SearchEngine's case, it gets caught every time further up the page (it never even reaches the upper/lower casing of only first character part)
*PrefixSearch eventually sends it through ApiQueryBase::titleToKey()
*AjaxFunctions immediately sends it to Title::newFromText()