API: libcib: Deprecate cib_scope_local cib_call_options value

This option is processed only when the CIB manager is in legacy mode,
for backward compatibility in mixed-version clusters. It will be removed
in a future release when legacy mode is no longer supported.

This commit also:

• clarifies a trace message
• adds a comment explaining the behavior of cib_scope_local and the reason for its deprecation

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>