psu-ng: Create errors for detected faults

Add in a function for creating errors using the Create D-Bus call.

Update the analyze function to create errors when faults are found.

We would want to log a fault per power supply, so move the faultLogged
concept down to the PowerSupply object itself.

Signed-off-by: Brandon Wyman <bjwyman@gmail.com>
Change-Id: I94d22b2b8a495abde87fb921c9177c6d25225ef7
diff --git a/phosphor-power-supply/power_supply.cpp b/phosphor-power-supply/power_supply.cpp
index 97acd6d..ab1caf9 100644
--- a/phosphor-power-supply/power_supply.cpp
+++ b/phosphor-power-supply/power_supply.cpp
@@ -129,6 +129,7 @@
     inputFault = false;
     mfrFault = false;
     vinUVFault = false;
+    faultLogged = false;
 
     // The PMBus device driver does not allow for writing CLEAR_FAULTS
     // directly. However, the pmbus hwmon device driver code will send a