Remove new live from default error_log formatter

error_log() function already insert a new line at end of the given
message, this commit just remove the new line at end to remove the new
live duplication.

src/Monolog/Handler/ErrorLogHandler.php

@@ -11,6 +11,7 @@
 
 namespace Monolog\Handler;
 
+use Monolog\Formatter\ErrorLogFormatter;
 use Monolog\Logger;
 
 /**
@@ -53,6 +54,14 @@ class ErrorLogHandler extends AbstractProcessingHandler
         );
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    protected function getDefaultFormatter()
+    {
+        return new ErrorLogFormatter();
+    }
+
     /**
      * {@inheritdoc}
      */