Revert "--json-exceptions"

This reverts commit a325524454.

Turns out this was predicated on an incorrect belief that json output
didn't already sometimes lack the "key" field. Since json output already
can when `giveup` was used, it seems unncessary to add a whole new
option for this.

Messages.hs

@@ -27,8 +27,6 @@ module Messages (
 	showEndFail,
 	showEndResult,
 	endResult,
-	ExceptionId(..),
-	showException,
 	toplevelWarning,
 	warning,
 	earlyWarning,
@@ -199,26 +197,6 @@ endResult :: Bool -> S.ByteString
 endResult True = "ok"
 endResult False = "failed"
 
-{- Unique ids for different exceptions. Do not change the constructors. -}
-data ExceptionId
-	= FileNotFound
-	| FileBeyondSymbolicLink
-	deriving (Show)
-
-{- Displays an message that is not associated with any file being
- - processed. -}
-showException :: Bool -> ExceptionId -> StringContainingQuotedPath -> Annex ()
-showException makeway eid msg = do
-	when makeway $
-		outputMessage JSON.none id "\n"
-	outputException (show eid) (mentionedfile msg)
-		("git-annex: " <> msg <> "\n")
-  where
-	mentionedfile (QuotedPath p) = Just p
-	mentionedfile (a :+: b) = mentionedfile a <|> mentionedfile b
-	mentionedfile (UnquotedString _) = Nothing
-	mentionedfile (UnquotedByteString _) = Nothing
-
 toplevelWarning :: Bool -> StringContainingQuotedPath -> Annex ()
 toplevelWarning makeway s = warning' makeway id ("git-annex: " <> s)