MAINT-5269 FIXED Viewer crashes if you open Help -> About Second Life while a...

MAINT-5269 FIXED Viewer crashes if you open Help -> About Second Life while a group member list is loading.

indra/newview/llfloaterabout.cpp

@@ -289,9 +289,6 @@ void LLServerReleaseNotesURLFetcher::httpCompleted()
 	LL_DEBUGS("ServerReleaseNotes") << dumpResponse() 
 									<< " [headers:" << getResponseHeaders() << "]" << LL_ENDL;
 
-	LLFloaterAbout* floater_about = LLFloaterReg::getTypedInstance<LLFloaterAbout>("sl_about");
-	if (floater_about)
-	{
 	std::string location = getResponseHeader(HTTP_IN_HEADER_LOCATION);
 	if (location.empty())
 	{
@@ -299,5 +296,4 @@ void LLServerReleaseNotesURLFetcher::httpCompleted()
 	}
 	LLAppViewer::instance()->setServerReleaseNotesURL(location);
 }
-}