Fix bug in net::RequestPriority -> HTTP/2 dependency conversion.

testing/variations/fieldtrial_testing_config_ios.json

 {
     "AutofillFieldMetadata": [
         {
             "group_name": "Enabled"
         }
     ],
     "AutofillProfileOrderByFrecency": [
         {
             "group_name": "EnabledLimitTo3",
             "params": {
@@ skipping 38 matching lines @@
     "QUIC": [
         {
             "group_name": "Enabled"
         }
     ],
     "SdchPersistence": [
         {
             "group_name": "Enabled"
         }
     ],
-    "SpdyEnableDependencies": [
-        {
-            "group_name": "Enable"
-        }
-    ],
     "SyncHttpContentCompression": [
         {
             "group_name": "Enabled"
         },
         {
             "group_name": "Disabled"
         }
     ],
     "TabSyncByRecency": [
         {
             "group_name": "Enabled"
         }
     ],
     "VarationsServiceControl": [
         {
             "group_name": "Interval_30min",
             "params": {
                 "fetch_period_min": "30"
             }
         }
     ]
 }