[PATCH 5/6] lib-sql: Make escape_string return int with error_r, fail instead of...

[PATCH 5/6] lib-sql: Make escape_string return int with error_r, fail instead of unsafe fallback

Change escape_string driver vfunc and sql_escape_string() to return int
with separate error_r output parameter. On failure (e.g. not connected),
return -1 instead of falling back to unsafe escaping.

Move escaping from sql_statement_bind_str() to sql_statement_get_query()
so errors can be propagated to callers. Add failed_error field to
sql_transaction_context for deferred error reporting at commit time.

Gbp-Pq: Name 0005-lib-sql-Make-escape_string-return-int-with-error_r-f.patch