Reduce the number of Flush (fsync) when closing a TFile.
Reduce the number of Flush (fsync) when closing a TFile.

Rather than doing one call to Flush (fsync) per TDirectory during the execution of TFile::Close
we reduce this to just one call.  Doing so many sync was extremely slow on an ATA disk (order
of 5 minutes for 90000 TDirectories.  With this update the time is down to half a second.

olifre/root,zzxuanyuan/root,dfunke/root,arch1tect0r/root,gganis/root,smarinac/root,abhinavmoudgil95/root,lgiommi/root,karies/root,gbitzes/root,mhuwiler/rootauto,veprbl/root,buuck/root,root-mirror/root,lgiommi/root,satyarth934/root,omazapa/root,Duraznos/root,georgtroska/root,abhinavmoudgil95/root,gganis/root,bbockelm/root,jrtomps/root,Y--/root,satyarth934/root,davidlt/root,georgtroska/root,thomaskeck/root,davidlt/root,veprbl/root,gbitzes/root,olifre/root,pspe/root,0x0all/ROOT,agarciamontoro/root,0x0all/ROOT,sirinath/root,zzxuanyuan/root-compressor-dummy,sirinath/root,davidlt/root,nilqed/root,abhinavmoudgil95/root,sirinath/root,abhinavmoudgil95/root,gganis/root,zzxuanyuan/root-compressor-dummy,zzxuanyuan/root-compressor-dummy,karies/root,pspe/root,CristinaCristescu/root,krafczyk/root,vukasinmilosevic/root,zzxuanyuan/root,gganis/root,smarinac/root,omazapa/root,lgiommi/root,vukasinmilosevic/root,mattkretz/root,georgtroska/root,dfunke/root,dfunke/root,root-mirror/root,CristinaCristescu/root,omazapa/root,buuck/root,sawenzel/root,dfunke/root,nilqed/root,olifre/root,omazapa/root-old,agarciamontoro/root,perovic/root,buuck/root,satyarth934/root,jrtomps/root,buuck/root,georgtroska/root,mkret2/root,thomaskeck/root,esakellari/root,krafczyk/root,evgeny-boger/root,simonpf/root,0x0all/ROOT,davidlt/root,arch1tect0r/root,davidlt/root,bbockelm/root,perovic/root,bbockelm/root,dfunke/root,veprbl/root,nilqed/root,zzxuanyuan/root,Y--/root,Duraznos/root,nilqed/root,krafczyk/root,satyarth934/root,olifre/root,smarinac/root,olifre/root,vukasinmilosevic/root,thomaskeck/root,arch1tect0r/root,mkret2/root,BerserkerTroll/root,karies/root,evgeny-boger/root,sirinath/root,mattkretz/root,omazapa/root-old,sbinet/cxx-root,lgiommi/root,simonpf/root,evgeny-boger/root,nilqed/root,BerserkerTroll/root,zzxuanyuan/root-compressor-dummy,gganis/root,gganis/root,krafczyk/root,zzxuanyuan/root-compressor-dummy,jrtomps/root,nilqed/root,veprbl/root,agarciamontoro/root,esakellari/my_root_for_test,agarciamontoro/root,smarinac/root,esakellari/root,veprbl/root,sawenzel/root,sbinet/cxx-root,abhinavmoudgil95/root,simonpf/root,bbockelm/root,georgtroska/root,davidlt/root,evgeny-boger/root,zzxuanyuan/root,karies/root,omazapa/root-old,zzxuanyuan/root-compressor-dummy,esakellari/root,zzxuanyuan/root-compressor-dummy,thomaskeck/root,Y--/root,smarinac/root,jrtomps/root,mattkretz/root,olifre/root,CristinaCristescu/root,buuck/root,gbitzes/root,mattkretz/root,jrtomps/root,bbockelm/root,satyarth934/root,0x0all/ROOT,zzxuanyuan/root-compressor-dummy,olifre/root,vukasinmilosevic/root,nilqed/root,thomaskeck/root,georgtroska/root,sbinet/cxx-root,agarciamontoro/root,buuck/root,abhinavmoudgil95/root,sbinet/cxx-root,zzxuanyuan/root,sbinet/cxx-root,omazapa/root,mhuwiler/rootauto,abhinavmoudgil95/root,evgeny-boger/root,sirinath/root,olifre/root,buuck/root,bbockelm/root,karies/root,gbitzes/root,beniz/root,sbinet/cxx-root,CristinaCristescu/root,BerserkerTroll/root,pspe/root,esakellari/root,simonpf/root,sbinet/cxx-root,esakellari/root,agarciamontoro/root,Duraznos/root,omazapa/root-old,thomaskeck/root,evgeny-boger/root,beniz/root,perovic/root,esakellari/my_root_for_test,simonpf/root,beniz/root,simonpf/root,thomaskeck/root,davidlt/root,mhuwiler/rootauto,simonpf/root,smarinac/root,beniz/root,esakellari/root,sbinet/cxx-root,zzxuanyuan/root,sawenzel/root,pspe/root,BerserkerTroll/root,davidlt/root,davidlt/root,jrtomps/root,agarciamontoro/root,perovic/root,sirinath/root,jrtomps/root,mkret2/root,Y--/root,simonpf/root,bbockelm/root,esakellari/my_root_for_test,beniz/root,omazapa/root-old,abhinavmoudgil95/root,esakellari/root,buuck/root,mhuwiler/rootauto,root-mirror/root,pspe/root,omazapa/root-old,smarinac/root,karies/root,jrtomps/root,veprbl/root,mkret2/root,evgeny-boger/root,Duraznos/root,dfunke/root,simonpf/root,davidlt/root,esakellari/my_root_for_test,sbinet/cxx-root,esakellari/my_root_for_test,0x0all/ROOT,perovic/root,omazapa/root,BerserkerTroll/root,mhuwiler/rootauto,simonpf/root,karies/root,0x0all/ROOT,vukasinmilosevic/root,sawenzel/root,pspe/root,Duraznos/root,vukasinmilosevic/root,esakellari/root,sirinath/root,esakellari/root,evgeny-boger/root,vukasinmilosevic/root,Y--/root,perovic/root,gbitzes/root,gganis/root,satyarth934/root,buuck/root,olifre/root,krafczyk/root,BerserkerTroll/root,krafczyk/root,thomaskeck/root,Y--/root,perovic/root,zzxuanyuan/root-compressor-dummy,CristinaCristescu/root,davidlt/root,beniz/root,esakellari/my_root_for_test,sbinet/cxx-root,pspe/root,bbockelm/root,georgtroska/root,omazapa/root-old,smarinac/root,omazapa/root,sirinath/root,mattkretz/root,gganis/root,vukasinmilosevic/root,root-mirror/root,esakellari/root,root-mirror/root,veprbl/root,sawenzel/root,lgiommi/root,gbitzes/root,sawenzel/root,esakellari/my_root_for_test,BerserkerTroll/root,gbitzes/root,beniz/root,lgiommi/root,veprbl/root,sawenzel/root,mhuwiler/rootauto,Duraznos/root,gbitzes/root,olifre/root,krafczyk/root,gganis/root,Duraznos/root,zzxuanyuan/root,buuck/root,omazapa/root,agarciamontoro/root,mkret2/root,dfunke/root,vukasinmilosevic/root,simonpf/root,smarinac/root,dfunke/root,pspe/root,0x0all/ROOT,smarinac/root,arch1tect0r/root,sawenzel/root,agarciamontoro/root,lgiommi/root,dfunke/root,vukasinmilosevic/root,root-mirror/root,nilqed/root,beniz/root,karies/root,krafczyk/root,esakellari/my_root_for_test,bbockelm/root,mkret2/root,arch1tect0r/root,veprbl/root,agarciamontoro/root,mhuwiler/rootauto,Y--/root,CristinaCristescu/root,esakellari/root,mhuwiler/rootauto,perovic/root,satyarth934/root,Y--/root,CristinaCristescu/root,zzxuanyuan/root,perovic/root,mattkretz/root,mattkretz/root,georgtroska/root,gbitzes/root,zzxuanyuan/root,omazapa/root-old,gbitzes/root,Duraznos/root,BerserkerTroll/root,sirinath/root,arch1tect0r/root,zzxuanyuan/root-compressor-dummy,zzxuanyuan/root,veprbl/root,BerserkerTroll/root,bbockelm/root,abhinavmoudgil95/root,root-mirror/root,gganis/root,olifre/root,jrtomps/root,CristinaCristescu/root,satyarth934/root,CristinaCristescu/root,arch1tect0r/root,sbinet/cxx-root,krafczyk/root,gbitzes/root,evgeny-boger/root,omazapa/root-old,pspe/root,satyarth934/root,dfunke/root,zzxuanyuan/root,Duraznos/root,0x0all/ROOT,Duraznos/root,satyarth934/root,mattkretz/root,mattkretz/root,mattkretz/root,omazapa/root-old,beniz/root,0x0all/ROOT,Y--/root,krafczyk/root,gganis/root,nilqed/root,omazapa/root-old,perovic/root,omazapa/root,BerserkerTroll/root,CristinaCristescu/root,lgiommi/root,sirinath/root,krafczyk/root,perovic/root,sirinath/root,buuck/root,lgiommi/root,arch1tect0r/root,CristinaCristescu/root,mkret2/root,agarciamontoro/root,sawenzel/root,georgtroska/root,zzxuanyuan/root,evgeny-boger/root,mkret2/root,omazapa/root,mkret2/root,esakellari/my_root_for_test,karies/root,thomaskeck/root,abhinavmoudgil95/root,beniz/root,karies/root,sawenzel/root,root-mirror/root,jrtomps/root,omazapa/root,vukasinmilosevic/root,Y--/root,lgiommi/root,pspe/root,arch1tect0r/root,arch1tect0r/root,abhinavmoudgil95/root,thomaskeck/root,pspe/root,georgtroska/root,mhuwiler/rootauto,zzxuanyuan/root-compressor-dummy,veprbl/root,Y--/root,root-mirror/root,mattkretz/root,mhuwiler/rootauto,root-mirror/root,beniz/root,georgtroska/root,root-mirror/root,mhuwiler/rootauto,nilqed/root,arch1tect0r/root,evgeny-boger/root,esakellari/my_root_for_test,lgiommi/root,omazapa/root,dfunke/root,jrtomps/root,Duraznos/root,mkret2/root,sawenzel/root,karies/root,mkret2/root,bbockelm/root,satyarth934/root,nilqed/root,BerserkerTroll/root