Send ambient and altitude to OCC

After the OCCs go active or anytime the ambient temperature changes the
ambient temperature and alititude will get sent to each OCC.
The altitude is only read once. If the altitude was not valid,
another attempt to read it will be done when the ambient temperature
is going to be re-sent.

Tested on Everest and Rainier systems

Change-Id: Icd64c50c05469bc985cfcaa3fcc74c3db5b41429
Signed-off-by: Chris Cain <cjcain@us.ibm.com>
diff --git a/utils.hpp b/utils.hpp
index 67d7a31..9e6c19b 100644
--- a/utils.hpp
+++ b/utils.hpp
@@ -19,7 +19,7 @@
 constexpr auto DBUS_PROPERTY_IFACE = "org.freedesktop.DBus.Properties";
 
 // The value of the property(type: variant, contains some basic types)
-using PropertyValue = std::variant<uint32_t, bool>;
+using PropertyValue = std::variant<uint32_t, bool, double>;
 
 /** @brief Get the bus connection. */
 static auto& getBus()