remove grayscale covtype as duplicate of Pan

rgbnir_definition.json

@@ -238,25 +238,6 @@
         ],
         "data_type": "Uint16",
         "name": "RGB"
-    }, {
-        "bands": [{
-            "definition": "http://www.opengis.net/def/property/OGC/0/Radiance",
-            "description": "Gray Channel",
-            "gdal_interpretation": "GrayBand",
-            "identifier": "gray",
-            "name": "gray",
-            "nil_values": [{
-                "reason": "http://www.opengis.net/def/nil/OGC/0/unknown",
-                "value": 0
-            }],
-            "uom": "W.m-2.Sr-1",
-            "significant_figures": 5,
-            "allowed_value_ranges": [
-                [0, 65535]
-            ]
-        }],
-        "data_type": "Uint16",
-        "name": "grayscale"
     }, {
         "bands": [{
                 "definition": "http://www.opengis.net/def/property/OGC/0/Radiance",