Move dbus connection into base sensor object

This seems common through most sensors, might as
well move it for consistency.

Tested: sensors operational as normal

Change-Id: I4e6c55cbb7171ee51700015f8c2ef8c05c90fb4e
Signed-off-by: James Feist <james.feist@linux.intel.com>
diff --git a/src/IpmbSensor.cpp b/src/IpmbSensor.cpp
index a7c1e09..dccdffb 100644
--- a/src/IpmbSensor.cpp
+++ b/src/IpmbSensor.cpp
@@ -69,9 +69,8 @@
     Sensor(boost::replace_all_copy(sensorName, " ", "_"),
            std::move(thresholdData), sensorConfiguration,
            "xyz.openbmc_project.Configuration.ExitAirTemp", ipmbMaxReading,
-           ipmbMinReading, PowerState::on),
-    deviceAddress(deviceAddress), objectServer(objectServer),
-    dbusConnection(conn), waitTimer(io)
+           ipmbMinReading, conn, PowerState::on),
+    deviceAddress(deviceAddress), objectServer(objectServer), waitTimer(io)
 {
     std::string dbusPath = sensorPathPrefix + sensorTypeName + "/" + name;