frrender: T9442: cache the FRR configuration only after it was applied

The configuration was stored as the cached one before FRR had reloaded
it. If the reload failed, or FRR was down, the next commit found the
configuration unchanged, skipped the reload and reported success while
FRR kept running the old configuration.

Keep the rendered configuration aside and make it the cached one only
after the reload succeeded. A render which does not reach the reload is
not cached either.

If the reload fails, FRR may run a part of the new configuration. The
cache is dropped then, so even a return to the previous configuration
reloads FRR. A reload that succeeds on the last try no longer raises an
error.

0 files changed, 0 insertions, 0 deletions