tools: fix reload script for SRv6 locators and formats

tools: fix reload script for SRv6 locators and formats

Current code implementation does not have a "no" form of handling for
the following commands under segment-routing srv6
 - no formats
 - no locators
 - no prefix <> under locator XYZ

Fix the handling of segment-routing srv6 locators and formats commands
 - Ignore "no formats" and "no locators" command
 - replace "no prefix" under locator XYZ as "no locator XYZ" as prefix
   is a mandatory property of locator

Signed-off-by: Rajasekar Raja <rajasekarr@nvidia.com>