Fix chassis bookmark link url

Fix the chassis bookmark link url and modify the validate_link() at
tests/api/base.py to enable it to validate bookmark links. The tests on
all the resources were also updated to check if the bookmark link was
generated correctly.

Closes-Bug: #1304564
Change-Id: I8383dd1d48569dadbbafb4587c89973f8440b396
Merge "Fix chassis bookmark link url"