remove synchronization from CsvMapper (#468)

Author: pjfanning

csv/src/main/java/com/fasterxml/jackson/dataformat/csv/CsvMapper.java

@@ -472,19 +472,15 @@ protected CsvSchema _schemaFor(JavaType pojoType, LRUMap<ViewKey,CsvSchema> sche
             boolean typed, Class<?> view)
     {
         final ViewKey viewKey = new ViewKey(pojoType, view);
-        synchronized (schemas) {
-            CsvSchema s = schemas.get(viewKey);
-            if (s != null) {
-                return s;
-            }
+        CsvSchema s = schemas.get(viewKey);
+        if (s != null) {
+            return s;
         }
         final AnnotationIntrospector intr = _deserializationConfig.getAnnotationIntrospector();
         CsvSchema.Builder builder = CsvSchema.builder();
         _addSchemaProperties(builder, intr, typed, pojoType, null, view);
         CsvSchema result = builder.build();
-        synchronized (schemas) {
-            schemas.put(viewKey, result);
-        }
+        schemas.put(viewKey, result);
         return result;
     }