presence: Create ErrorReporter class

This class will, eventually, create event logs for missing fans.

This first commit will just create a stubbed out class if there is a
'reporting' section in the configuration JSON.  From the JSON, the class
will pull out the value for the number of seconds to wait between first
detecting a fan is missing and creating the event log for it.

This requires a slight change to the existing JSON format, however the
JsonConfig class was updated to support both the old and new formats.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I991ea7cf0457448411e65f4c8e274bb2584d15f4
diff --git a/presence/Makefile.am b/presence/Makefile.am
index 2f1d787..a26fac9 100644
--- a/presence/Makefile.am
+++ b/presence/Makefile.am
@@ -6,6 +6,7 @@
 
 phosphor_fan_presence_tach_SOURCES = \
 	anyof.cpp \
+	error_reporter.cpp \
 	fallback.cpp \
 	fan.cpp \
 	gpio.cpp \