Binding generator v2 - fix getter method name

Binding generator v2 - fix getter method name

- for yang snippet:
  container cont {
    leaf class {
      type string;
    }
  }
  the leaf name was reserved, but the result of method normalizing "get_class"
  is "getClass", so here just let "get" append the result of class normalizing
  "class" which should be "ClassReservedKeyword" ,that would be "getClassReservedKeyword".

Change-Id: Ibee98a5d82145b1f39509d05da6923fae0cb19f9
Signed-off-by: Jie Han <han.jie@zte.com.cn>
(cherry picked from commit f1ccafdea3ef03ef82f5e9f141b94ab2418d0d94)