include credPairRemoteFields in RemoteConfigParsers

Avoids parse error when the fields are added to RemoteConfig at setup
time and it then gets parsed, also at setup time. After setup time, such
internally added fields are not a problem, because they're Accepted. So
it may not be necessary in all cases to list such internally added
fields, but I think it's a good idea to always do so.

Remote/WebDAV.hs

@@ -49,6 +49,7 @@ remote = specialRemoteType $ RemoteType
 	, generate = gen
 	, configParser = mkRemoteConfigParser
 		[ optionalStringParser urlField
+		, optionalStringParser davcredsField
 		]
 	, setup = webdavSetup
 	, exportSupported = exportIsSupported
@@ -58,6 +59,9 @@ remote = specialRemoteType $ RemoteType
 urlField :: RemoteConfigField
 urlField = Accepted "url"
 
+davcredsField :: RemoteConfigField
+davcredsField = Accepted "davcreds"
+
 gen :: Git.Repo -> UUID -> ParsedRemoteConfig -> RemoteGitConfig -> RemoteStateHandle -> Annex (Maybe Remote)
 gen r u c gc rs = new <$> remoteCost gc expensiveRemoteCost
   where
@@ -351,7 +355,7 @@ davCreds :: UUID -> CredPairStorage
 davCreds u = CredPairStorage
 	{ credPairFile = fromUUID u
 	, credPairEnvironment = ("WEBDAV_USERNAME", "WEBDAV_PASSWORD")
-	, credPairRemoteField = Accepted "davcreds"
+	, credPairRemoteField = davcredsField
 	}
 
 {- Content-Type to use for files uploaded to WebDAV. -}