add a trace mechanism to trace sql stuff

base/mysql.hh:
    Trace sql queries
base/traceflags.py:
    Add a trace flag to trace sql queries

--HG--
extra : convert_revision : dc25abb474db7334529b791a7aa90f8178ea59ea

base/mysql.hh

@@ -180,6 +180,7 @@ class Connection
     bool
     query(const std::string &sql)
     {
+        DPRINTF(SQL, "Sending SQL query to server:\n%s", sql);
         error.clear();
         if (mysql_real_query(&mysql, sql.c_str(), sql.size()))
             error.set(mysql_error(&mysql));

base/traceflags.py

@@ -121,7 +121,8 @@ baseFlags = [
     'IdeDisk',
     'Tsunami',
     'Uart',
-    'Split'
+    'Split',
+    'SQL'
     ]
 
 #