Add callback contexts

Add the notion of a callback context. This enables callbacks
to have logic around the conditions they were invoked in.

There are two context on which call back can be invoked
1) Startup: during startup all the call backs will be called
2) Signal: As part of condition match on the watched properties.

Callback would behave differently based on the context.
eg: eventCallback
1) Startup: Don't take any action.
2) Signal: Create the Dbus Object for the event.

Change-Id: If455558798ac3e44bbd8a93de0ce1b09d2e308ae
Signed-off-by: Ratan Gupta <ratagupt@in.ibm.com>
diff --git a/src/resolve_errors.cpp b/src/resolve_errors.cpp
index 67f7313..54f0b78 100644
--- a/src/resolve_errors.cpp
+++ b/src/resolve_errors.cpp
@@ -34,7 +34,7 @@
 using EndpointList = std::vector<std::string>;
 using EndpointsProperty = sdbusplus::message::variant<EndpointList>;
 
-void ResolveCallout::operator()()
+void ResolveCallout::operator()(Context ctx)
 {
     //Resolve all errors for this callout:
     // 1) Read the 'endpoints' property for the callout/fault object