Change default log level

The default log level is currently LOG_ERR. Tools can override this
default but there is a non-trivial amount of setup that needs to
happen before the log level can be changed. Since tools may want to
use the warn level for things such as deprecated flags, change the
default to LOG_WARNING to ensure messages get printed.
diff --git a/tools/log.c b/tools/log.c
index e29a150..3317a35 100644
--- a/tools/log.c
+++ b/tools/log.c
@@ -29,7 +29,7 @@
 #define PRIO_MAX_SIZE 32
 
 static bool log_use_syslog;
-static int log_priority = LOG_ERR;
+static int log_priority = LOG_WARNING;
 
 static const char *prio_to_str(char buf[static PRIO_MAX_SIZE], int prio)
 {