system_wrappers: rename interface -> include

BUG=webrtc:5095
R=tommi@webrtc.org

Review URL: https://codereview.webrtc.org/1413333002 .

Cr-Commit-Position: refs/heads/master@{#10438}
diff --git a/webrtc/system_wrappers/source/file_impl.cc b/webrtc/system_wrappers/source/file_impl.cc
index 89a9185..0ee0dea 100644
--- a/webrtc/system_wrappers/source/file_impl.cc
+++ b/webrtc/system_wrappers/source/file_impl.cc
@@ -20,7 +20,7 @@
 #endif
 
 #include "webrtc/base/checks.h"
-#include "webrtc/system_wrappers/interface/rw_lock_wrapper.h"
+#include "webrtc/system_wrappers/include/rw_lock_wrapper.h"
 
 namespace webrtc {