unit-test: add dep for phosphor-dbus-interfaces

Change-Id: I9fcb8ba71982634b7a74ecd3ed4991edf77a97f3
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/scripts/unit-test.py b/scripts/unit-test.py
index 400ce15..652dfc2 100755
--- a/scripts/unit-test.py
+++ b/scripts/unit-test.py
@@ -141,6 +141,9 @@
             'host-ipmid': 'phosphor-host-ipmid',
             'sdbusplus': 'sdbusplus',
             'log.hpp': 'phosphor-logging'
+        },
+        'PKG_CHECK_MODULES': {
+            'phosphor-dbus-interfaces': 'phosphor-dbus-interfaces'
         }
     }