Bug 1165515 - Part 13-2: Replace usage of PRLogModuleLevel and PR_LOG_*. rs=froydnj

This is straightforward mapping of PR_LOG levels to their LogLevel
counterparts:
  PR_LOG_ERROR   -> LogLevel::Error
  PR_LOG_WARNING -> LogLevel::Warning
  PR_LOG_WARN    -> LogLevel::Warning
  PR_LOG_INFO    -> LogLevel::Info
  PR_LOG_DEBUG   -> LogLevel::Debug
  PR_LOG_NOTICE  -> LogLevel::Debug
  PR_LOG_VERBOSE -> LogLevel::Verbose

Instances of PRLogModuleLevel were mapped to a fully qualified
mozilla::LogLevel, instances of PR_LOG levels in #defines were mapped to a
fully qualified mozilla::LogLevel::* level, and all other instances were
mapped to us a shorter format of LogLevel::*.

Bustage for usage of the non-fully qualified LogLevel were fixed by adding
|using mozilla::LogLevel;| where appropriate.

xpcom/ds/nsObserverService.cpp

@@ -25,7 +25,7 @@
 //    set NSPR_LOG_MODULES=ObserverService:5
 //    set NSPR_LOG_FILE=nspr.log
 //
-// this enables PR_LOG_DEBUG level information and places all output in
+// this enables LogLevel::Debug level information and places all output in
 // the file nspr.log
 static PRLogModuleInfo*
 GetObserverServiceLog()
@@ -36,7 +36,7 @@ GetObserverServiceLog()
   }
   return sLog;
 }
-#define LOG(x)  MOZ_LOG(GetObserverServiceLog(), PR_LOG_DEBUG, x)
+#define LOG(x)  MOZ_LOG(GetObserverServiceLog(), mozilla::LogLevel::Debug, x)
 
 namespace mozilla {