Make the behavior when we cannot write to a log or audit file

configurable.  File log failures are ignored by default for consistency
with syslog.  Audit errors are ignored by default to allow the admin
to fix the issue.  I/O log file errors are still fatal by default
since if I/O logging is activated it is usually to have an audit trail.
Bug #751

src/sudo.c

@@ -675,6 +675,9 @@ command_info_to_details(char * const info[], struct command_details *details)
 		    break;
 		}
 		break;
+	    case 'i':
+		SET_FLAG("ignore_iolog_errors=", CD_IGNORE_IOLOG_ERRS)
+		break;
 	    case 'l':
 		SET_STRING("login_class=", login_class)
 		break;