The code in function of get_all_requirements is duplicated
The code in function of get_all_requirements is duplicated

  In nodetype.py, the most code in functon of get_all_requirements
is not needed，becuase the property of requirements has realized
the main logical in current get_all_requirements.
  So the duplicated code will be deleted.

Closes-Bug: #1578733

Change-Id: Ib03868a42df5eb38aee9c51864a59243f28a2bb6
Signed-off-by: shangxdy <107c0ad1366302926223e36142fcb0dd27f1b990@zte.com.cn>

openstack/tosca-parser,openstack/tosca-parser