Bug 2236: Fixed bugs in PathMap.

  * equals(Object): mapIndex field values need to be compared using
    Objects.equals().
  * hashCode(): Fixed NPE if mapIndex is null.

Change-Id: Iadd25f620dba1af7fb08c262f22a97ee978e08a3
Signed-off-by: Shigeru Yasuda <s-yasuda@da.jp.nec.com>
(cherry picked from commit fc6d27d53a08686835a1b0092f2c82df91fc1f38)
Merge "Bug 2236: Fixed bugs in PathMap." into stable/helium