If --dry-run specified, ensure minimum log level is INFO

When executed with --dry-run, repmgr outputs detail about what would
happen using log level INFO. If the log_level is configured to
NOTICE or higher, it's possible some or all of the --dry-run output
might not be displayed.

Addresses GitHub #441.

log.c

@@ -329,6 +329,13 @@ logger_set_terse(void)
 }
 
 
+void
+logger_set_min_level(int min_log_level)
+{
+	if (min_log_level > log_level)
+		log_level = min_log_level;
+}
+
 int
 detect_log_level(const char *level)
 {