Retry to acquire a db connection when starting a transaction

This fixes db issues just like we do for regular queries.
Also we now use the .on('connection') to setup the session and db
this is how the docs recommend it

src/database.js

@@ -47,6 +47,11 @@ function initialize(options, callback) {
         ssl: false
     });
 
+    gConnectionPool.on('connection', function (connection) {
+        connection.query('USE ' + config.database().name);
+        connection.query('SET SESSION sql_mode = \'strict_all_tables\'');
+    });
+
     reconnect(callback);
 }
 
@@ -59,24 +64,6 @@ function uninitialize(callback) {
     }
 }
 
-function setupConnection(connection, callback) {
-    assert.strictEqual(typeof connection, 'object');
-    assert.strictEqual(typeof callback, 'function');
-
-    connection.on('error', console.error);
-
-    async.series([
-        connection.query.bind(connection, 'USE ' + config.database().name),
-        connection.query.bind(connection, 'SET SESSION sql_mode = \'strict_all_tables\'')
-    ], function (error) {
-        connection.removeListener('error', console.error);
-
-        if (error) connection.release();
-
-        callback(error);
-    });
-}
-
 function reconnect(callback) {
     callback = callback ? once(callback) : function () {};
 
@@ -97,13 +84,9 @@ function reconnect(callback) {
             setTimeout(reconnect.bind(null, callback), 1000);
         });
 
-        setupConnection(connection, function (error) {
-            if (error) return setTimeout(reconnect.bind(null, callback), 1000);
+        gDefaultConnection = connection;
 
-            gDefaultConnection = connection;
-
-            callback(null);
-        });
+        callback(null);
     });
 }
 
@@ -131,16 +114,15 @@ function beginTransaction(callback) {
     if (gConnectionPool === null) return callback(new Error('No database connection pool.'));
 
     gConnectionPool.getConnection(function (error, connection) {
-        if (error) return callback(error);
+        if (error) {
+            console.error('Unable to get connection to database. Try again in a bit.', error.message);
+            return setTimeout(beginTransaction.bind(null, callback), 1000);
+        }
 
-        setupConnection(connection, function (error) {
+        connection.beginTransaction(function (error) {
             if (error) return callback(error);
 
-            connection.beginTransaction(function (error) {
-                if (error) return callback(error);
-
-                return callback(null, connection);
-            });
+            return callback(null, connection);
         });
     });
 }