Replaced use of ERROR with ERR to fix Windows build error.

ERROR is defined to 0 inside of Windows headers for use
with the Windows API. This causes a conflict with our use
 of ERROR.

Change-Id: Ic15563420dd78e41240e4053a54b18ea6967c61f
Reviewed-on: http://review.couchbase.org/28718
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Leonid Barenblit <lbarenblit@gmail.com>
Tested-by: Brett Lawson <brett19@gmail.com>