Comment describing SetVLOGLevel is not accurate

[hari90]

Currently the comment states the following:

// NOTE: To change the log level for VLOG(_IS_ON) sites
//	 that have already executed after/during InitGoogleLogging,
//	 one needs to supply the exact --vmodule pattern that applied to them.
//       (If no --vmodule pattern applied to them
//       the value of FLAGS_v will continue to control them.)

But #650 added support for updating vmodule levels after vmodule level has been cached.

The comment should be

// NOTE: To change the log level for VLOG(_IS_ON) sites
//	 that matched a prior --vmodule pattern then the exact pattern has to be supplied again.
//       (If no --vmodule pattern applied to them before then the first matching pattern will start to control them.)

[sergiud]

@romange Could you please verify the suggestion?

[hari90]

@sergiud @romange I submitted #1109 for this. Can you please review it?