install blob_interface_mock header

To enable unit-tests that deal with this library's objects, install the
blob_interface_mock header.

Change-Id: I230c9195c1c14a61c8b6bc838bb0a17ab8798053
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/src/Makefile.am b/src/Makefile.am
index 26c82a7..c23c6ee 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -19,4 +19,5 @@
 nobase_include_HEADERS += ipmiblob/internal/sys.hpp
 libipmiblob_la_SOURCES += ipmiblob/internal/sys.cpp
 
+nobase_include_HEADERS += ipmiblob/test/blob_interface_mock.hpp
 nobase_include_HEADERS += ipmiblob/test/ipmi_interface_mock.hpp