Protect THStack::GetXaxis and THStack::GetYaxis in case the THStack does not have any histogram.
Protect THStack::GetXaxis and THStack::GetYaxis in case the THStack does not have any histogram.


git-svn-id: acec3fd5b7ea1eb9e79d6329d318e8118ee2e14f@21541 27541ba8-7e3a-0410-8455-c3a389f83636

strykejern/TTreeReader,jrtomps/root,pspe/root,Duraznos/root,sawenzel/root,Dr15Jones/root,davidlt/root,lgiommi/root,mkret2/root,agarciamontoro/root,lgiommi/root,ffurano/root5,evgeny-boger/root,lgiommi/root,jrtomps/root,strykejern/TTreeReader,arch1tect0r/root,buuck/root,Dr15Jones/root,veprbl/root,satyarth934/root,pspe/root,tc3t/qoot,davidlt/root,zzxuanyuan/root,arch1tect0r/root,esakellari/root,simonpf/root,dfunke/root,abhinavmoudgil95/root,bbockelm/root,veprbl/root,CristinaCristescu/root,beniz/root,omazapa/root-old,olifre/root,strykejern/TTreeReader,omazapa/root-old,perovic/root,olifre/root,karies/root,buuck/root,sbinet/cxx-root,omazapa/root-old,dfunke/root,mkret2/root,krafczyk/root,evgeny-boger/root,root-mirror/root,agarciamontoro/root,Dr15Jones/root,0x0all/ROOT,CristinaCristescu/root,karies/root,evgeny-boger/root,tc3t/qoot,0x0all/ROOT,gganis/root,gbitzes/root,gganis/root,krafczyk/root,sawenzel/root,arch1tect0r/root,sirinath/root,root-mirror/root,omazapa/root-old,abhinavmoudgil95/root,mattkretz/root,omazapa/root-old,pspe/root,vukasinmilosevic/root,Y--/root,smarinac/root,gganis/root,karies/root,krafczyk/root,thomaskeck/root,perovic/root,Dr15Jones/root,gbitzes/root,omazapa/root,alexschlueter/cern-root,Duraznos/root,davidlt/root,sirinath/root,esakellari/root,omazapa/root,zzxuanyuan/root-compressor-dummy,vukasinmilosevic/root,BerserkerTroll/root,satyarth934/root,bbockelm/root,kirbyherm/root-r-tools,mhuwiler/rootauto,Y--/root,sbinet/cxx-root,esakellari/root,satyarth934/root,smarinac/root,sbinet/cxx-root,omazapa/root,esakellari/root,esakellari/root,ffurano/root5,mattkretz/root,jrtomps/root,davidlt/root,arch1tect0r/root,kirbyherm/root-r-tools,simonpf/root,jrtomps/root,beniz/root,georgtroska/root,gbitzes/root,nilqed/root,krafczyk/root,BerserkerTroll/root,lgiommi/root,sawenzel/root,mattkretz/root,mkret2/root,CristinaCristescu/root,zzxuanyuan/root,olifre/root,evgeny-boger/root,thomaskeck/root,zzxuanyuan/root,arch1tect0r/root,mattkretz/root,nilqed/root,jrtomps/root,bbockelm/root,abhinavmoudgil95/root,mkret2/root,zzxuanyuan/root-compressor-dummy,simonpf/root,dfunke/root,gbitzes/root,simonpf/root,Duraznos/root,esakellari/my_root_for_test,satyarth934/root,bbockelm/root,omazapa/root,cxx-hep/root-cern,veprbl/root,nilqed/root,arch1tect0r/root,omazapa/root-old,vukasinmilosevic/root,thomaskeck/root,omazapa/root,perovic/root,omazapa/root,Y--/root,zzxuanyuan/root,karies/root,bbockelm/root,mhuwiler/rootauto,buuck/root,omazapa/root-old,dfunke/root,satyarth934/root,root-mirror/root,Y--/root,abhinavmoudgil95/root,gbitzes/root,root-mirror/root,cxx-hep/root-cern,kirbyherm/root-r-tools,bbockelm/root,georgtroska/root,dfunke/root,vukasinmilosevic/root,lgiommi/root,strykejern/TTreeReader,krafczyk/root,evgeny-boger/root,0x0all/ROOT,perovic/root,gganis/root,lgiommi/root,karies/root,gganis/root,CristinaCristescu/root,Y--/root,evgeny-boger/root,beniz/root,BerserkerTroll/root,omazapa/root,veprbl/root,Duraznos/root,georgtroska/root,alexschlueter/cern-root,esakellari/my_root_for_test,sirinath/root,satyarth934/root,0x0all/ROOT,thomaskeck/root,zzxuanyuan/root,strykejern/TTreeReader,karies/root,alexschlueter/cern-root,satyarth934/root,nilqed/root,sirinath/root,beniz/root,jrtomps/root,mattkretz/root,georgtroska/root,gbitzes/root,karies/root,0x0all/ROOT,buuck/root,zzxuanyuan/root,Duraznos/root,simonpf/root,gbitzes/root,Y--/root,esakellari/root,lgiommi/root,tc3t/qoot,tc3t/qoot,buuck/root,arch1tect0r/root,zzxuanyuan/root,omazapa/root-old,krafczyk/root,esakellari/my_root_for_test,sawenzel/root,dfunke/root,Duraznos/root,smarinac/root,perovic/root,beniz/root,smarinac/root,nilqed/root,karies/root,strykejern/TTreeReader,sbinet/cxx-root,beniz/root,Duraznos/root,tc3t/qoot,veprbl/root,perovic/root,CristinaCristescu/root,zzxuanyuan/root-compressor-dummy,sirinath/root,gganis/root,alexschlueter/cern-root,mkret2/root,tc3t/qoot,mhuwiler/rootauto,karies/root,omazapa/root-old,cxx-hep/root-cern,esakellari/my_root_for_test,omazapa/root,root-mirror/root,agarciamontoro/root,olifre/root,olifre/root,agarciamontoro/root,smarinac/root,BerserkerTroll/root,CristinaCristescu/root,mattkretz/root,evgeny-boger/root,perovic/root,gganis/root,agarciamontoro/root,thomaskeck/root,vukasinmilosevic/root,mkret2/root,vukasinmilosevic/root,beniz/root,olifre/root,sbinet/cxx-root,cxx-hep/root-cern,vukasinmilosevic/root,nilqed/root,gbitzes/root,zzxuanyuan/root,buuck/root,thomaskeck/root,sawenzel/root,BerserkerTroll/root,pspe/root,jrtomps/root,buuck/root,0x0all/ROOT,karies/root,perovic/root,esakellari/my_root_for_test,nilqed/root,dfunke/root,sbinet/cxx-root,agarciamontoro/root,buuck/root,ffurano/root5,arch1tect0r/root,olifre/root,arch1tect0r/root,zzxuanyuan/root,sawenzel/root,mattkretz/root,beniz/root,krafczyk/root,sawenzel/root,sbinet/cxx-root,davidlt/root,perovic/root,jrtomps/root,esakellari/my_root_for_test,jrtomps/root,sirinath/root,veprbl/root,sirinath/root,veprbl/root,nilqed/root,BerserkerTroll/root,thomaskeck/root,mattkretz/root,sbinet/cxx-root,gganis/root,omazapa/root,abhinavmoudgil95/r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