stop installing manager header

Stop installing the manager header as it is no longer meant to be
exported, but rather used only internally within this repository.

Change-Id: I2ab21a31fd745e1b3e36fc39ffea5e26d373ff51
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/test/manager_open_unittest.cpp b/test/manager_open_unittest.cpp
index 72aff85..309d3f6 100644
--- a/test/manager_open_unittest.cpp
+++ b/test/manager_open_unittest.cpp
@@ -1,5 +1,6 @@
-#include <blobs-ipmid/manager.hpp>
-#include <blobs-ipmid/test/blob_mock.hpp>
+#include "blob_mock.hpp"
+#include "manager.hpp"
+
 #include <string>
 
 #include <gtest/gtest.h>