[AGE agtype_util.c] Fix issue #870 regarding orderability

Fixed issue #870 
 Odd behavior in context of orderability of different agtypes.

Implemented the solution suggested here:
#870 (comment)

Clearance given here:
#870 (comment)

src/backend/utils/adt/agtype_util.c

@@ -199,18 +199,22 @@ static int get_type_sort_priority(enum agtype_value_type type)
 {
     if (type == AGTV_OBJECT)
         return 0;
-    if (type == AGTV_VERTEX)
+    if (type == AGTV_PATH)
         return 1;
-    if (type == AGTV_ARRAY)
+    if (type == AGTV_EDGE)
         return 2;
-    if (type == AGTV_STRING)
+    if (type == AGTV_VERTEX)
         return 3;
-    if (type == AGTV_BOOL)
+    if (type == AGTV_ARRAY)
         return 4;
-    if (type == AGTV_NUMERIC || type == AGTV_INTEGER || type == AGTV_FLOAT)
+    if (type == AGTV_STRING)
         return 5;
-    if (type == AGTV_NULL)
+    if (type == AGTV_BOOL)
         return 6;
+    if (type == AGTV_NUMERIC || type == AGTV_INTEGER || type == AGTV_FLOAT)
+        return 7;
+    if (type == AGTV_NULL)
+        return 8;
     return -1;
 }