[ticket/12818] Fix the conditions in the call to $log->delete() in mcp_logs

PHPBB3-12818
[ticket/12818] Add tests

PHPBB3-12818
[ticket/12818] Don't use the id for i=

PHPBB3-12818
[ticket/12818] Use assertGreaterThanOrEqual in the tests

PHPBB3-12818
Merge pull request #2701 from Nicofuma/ticket/12818

[ticket/12818] Deleting a log entry in MCP produces a General error

* Nicofuma/ticket/12818:
  [ticket/12818] Use assertGreaterThanOrEqual in the tests
  [ticket/12818] Don't use the id for i=
  [ticket/12818] Add tests
  [ticket/12818] Fix the conditions in the call to $log->delete() in mcp_logs