build: Remove redundant jscs rule 'disallowQuotedKeysInObjects'

{ "allExcept": [ "reserved" ] } found in the wikimedia preset is
the same as the customized "allButReserved" present in MediaWiki,
except that the latter is deprecated as stated at:
http://jscs.info/rule/disallowQuotedKeysInObjects

Change-Id: I5de2a8f7ad42857ccdc793551d08c77e2aae8156

.jscsrc

@@ -4,7 +4,6 @@
 
 	"requireVarDeclFirst": null,
 
-	"disallowQuotedKeysInObjects": "allButReserved",
 	"requireDotNotation": { "allExcept": [ "keywords" ] },
 	"jsDoc": {
 		"checkAnnotations": {