Updates for new association interface

The association interface name changed to
xyz.openbmc_project.Association.Definitions and its property changed to
Associations.  Update the code accordingly.

Tested: Created an event log with a callout association, and verified
that the correct callout object was created.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: Id48b6f2093410757ca6119cda09544d81f708ba5
diff --git a/manager.cpp b/manager.cpp
index 2342743..7055e43 100644
--- a/manager.cpp
+++ b/manager.cpp
@@ -193,7 +193,7 @@
     }
 
     const auto& properties = associations->second;
-    auto assocProperty = properties.find("associations");
+    auto assocProperty = properties.find("Associations");
     auto assocValue =
         sdbusplus::message::variant_ns::get<AssociationsPropertyType>(
             assocProperty->second);