Bug 7377, Bug 7383: handling unnecessary error log

Bug 7377, Bug 7383: handling unnecessary error log

* There is no need of quering ElanInterface from config DS since
its reference is already part of the method argument
* Due to faster addition/removal of elan interface, elan interface is deleted
when its queried from installEntriesForElanInterface which caused 7377.
Now this is solved by directly passing elanInterface without querying
config DS.
* potential fix 7383 if mac is already deleted in elan-mac container.
This might occur when same mac is learned again on VLAN provider port

Change-Id: I7ed776a3b9a679ee22427b6f13e5e1a9adce57aa
Signed-off-by: Periyasamy Palanisamy <periyasamy.palanisamy@ericsson.com>
(cherry picked from commit b4c8027e430521030b37cfde799f42b0228ba4dd)