MXS-619: Allow backend authentication to complete

By deferring the closing of a DCB until the protocol tells that it's in a
stable state, we avoid closing the connection mid-authentication. This
makes sure that all connections have reached a stable state before they
are closed which in turn prevents the connections from counting towards
aborted connects (or failed authentications like it did with the old fix).

include/maxscale/clock.h

@@ -30,11 +30,17 @@ int64_t mxs_clock();
 /**
  * Convert heartbeats to seconds
  */
-#define MXS_CLOCK_TO_SEC(a) ((int64_t)a / 10)
+static inline int64_t MXS_CLOCK_TO_SEC(int64_t a)
+{
+    return a / 10;
+}
 
 /**
  * Convert seconds to heartbeats
  */
-#define MXS_SEC_TO_CLOCK(a) ((int64_t)a * 10)
+static inline int64_t MXS_SEC_TO_CLOCK(int64_t a)
+{
+    return a * 10;
+}
 
 MXS_END_DECLS