Fix capitalization of "Health status" in rip log

This fixes a regression from move to ruamel.yaml where all other fields in rip log have second word lowercased, except for "Health Status". This changes it to make it inline with all other fields again.

Signed-off-by: Matthew Peveler <matt.peveler@gmail.com>

whipper/result/logger.py

@@ -141,7 +141,7 @@ class WhipperLogger(result.Logger):
             message = "There were errors"
         else:
             message = "No errors occurred"
-        data["Health Status"] = message
+        data["Health status"] = message
         data["EOF"] = "End of status report"
         riplog["Conclusive status report"] = data