fixes FileLog doesn't delete on rotation if `rotate` = 0

lib/Cake/Log/Engine/FileLog.php

@@ -201,17 +201,21 @@ class FileLog extends BaseLog {
 		}
 
 		if ($this->_config['rotate'] === 0) {
-			return unlink($filepath);
+			$result = unlink($filepath);
+		} else {
+			$result = rename($filepath, $filepath . '.' . time());
 		}
 
-		if ($this->_config['rotate']) {
-			$files = glob($filepath . '.*');
-			while (count($files) >= $this->_config['rotate']) {
+		$files = glob($filepath . '.*');
+		if ($files) {
+			$filesToDelete = count($files) - $this->_config['rotate'];
+			while ($filesToDelete > 0) {
 				unlink(array_shift($files));
+				$filesToDelete--;
 			}
 		}
 
-		return rename($filepath, $filepath . '.' . time());
+		return $result;
 	}
 
 }

lib/Cake/Test/Case/Log/Engine/FileLogTest.php

@@ -142,6 +142,7 @@ class FileLogTest extends CakeTestCase {
 			'size' => 35,
 			'rotate' => 0
 		));
+		file_put_contents($path . 'debug.log.0000000000', "The oldest log file with over 35 bytes.\n");
 		$log->write('debug', 'Test debug');
 		$this->assertTrue(file_exists($path . 'debug.log'));