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/manager.cpp b/manager.cpp
index bc96b34..712d7db 100644
--- a/manager.cpp
+++ b/manager.cpp
@@ -14,8 +14,9 @@
  * limitations under the License.
  */
 
+#include "manager.hpp"
+
 #include <algorithm>
-#include <blobs-ipmid/manager.hpp>
 #include <memory>
 #include <string>
 #include <vector>