YANG PATCH using "replace" instead of "merge" when target is not list type

When using "merge" operation in YANG-PATCH edit section. OpenDaylight will replace the operation to "replace" if the target is not list type.

It does make sense, but it is not necessary. Since YANG Patch provides the option to specify operation in each edit, operator could use "merge" or "replace" for <edit-config> as they want rather than optimising on OpenDaylight side.