lock_guard: remove explicit template

Change-Id: Iec6d57d6a66557a66096c7a8f67e025c6ca5a64c
diff --git a/src/fileutils.cpp b/src/fileutils.cpp
index 72e78b6..9e23527 100644
--- a/src/fileutils.cpp
+++ b/src/fileutils.cpp
@@ -82,7 +82,7 @@
     static std::mutex fileLockLock {};
     static std::map<std::string, std::mutex> fileLocks {};
 
-    std::lock_guard<std::mutex> l(fileLockLock);
+    std::lock_guard l(fileLockLock);
     return fileLocks[path.string()];
 }