session: delete and add application namespace do not create the global session table

session: delete and add application namespace do not create the global session table

When an application namespace is added, we call session_table_is_alloced
to see if we need to allocate a new session table. That check returns true
even if we removed the session table.
The fix is when we delete an application's global session table,
we need to invalidate fib_index_to_table_index.

Fixed test_vcl test script to run two tests back to back.
The 1st test deletes the application namespace at the end.
The 2nd test adds the application namespace in the beginning.

Type: fix
Fixes: 67bae20b05cb46e5f6d19afeaf1f7a52a5309d59

Change-Id: I67f5cc1b726a07659597a9479df011717db08d0a
Signed-off-by: Steven Luong <[email protected]>