graph: fix ahead-behind logic
graph: fix ahead-behind logic

When we see PARENT1, it means there is a local commit and thus we are
ahead. Likewise, seeing PARENT2 means that the upstream branch has a
commit and we are one more behind.

The logic is currently reversed. Correct it.

This fixes #2501.

ardumont/libgit2,MrHacky/libgit2,mhp/libgit2,mrksrm/Mingijura,swisspol/DEMO-libgit2,iankronquist/libgit2,kenprice/libgit2,ardumont/libgit2,whoisj/libgit2,Snazz2001/libgit2,kenprice/libgit2,JIghtuse/libgit2,kissthink/libgit2,jflesch/libgit2-mariadb,since2014/libgit2,maxiaoqian/libgit2,swisspol/DEMO-libgit2,saurabhsuniljain/libgit2,sygool/libgit2,mhp/libgit2,stewid/libgit2,leoyanggit/libgit2,Tousiph/Demo1,since2014/libgit2,mcanthony/libgit2,maxiaoqian/libgit2,t0xicCode/libgit2,Snazz2001/libgit2,amyvmiwei/libgit2,rcorre/libgit2,t0xicCode/libgit2,rcorre/libgit2,ardumont/libgit2,KTXSoftware/libgit2,jeffhostetler/public_libgit2,dleehr/libgit2,maxiaoqian/libgit2,jflesch/libgit2-mariadb,yosefhackmon/libgit2,t0xicCode/libgit2,mrksrm/Mingijura,kenprice/libgit2,ardumont/libgit2,mhp/libgit2,claudelee/libgit2,dleehr/libgit2,rcorre/libgit2,falqas/libgit2,t0xicCode/libgit2,Corillian/libgit2,skabel/manguse,claudelee/libgit2,mrksrm/Mingijura,magnus98/TEST,MrHacky/libgit2,iankronquist/libgit2,leoyanggit/libgit2,iankronquist/libgit2,swisspol/DEMO-libgit2,magnus98/TEST,yosefhackmon/libgit2,jeffhostetler/public_libgit2,MrHacky/libgit2,yongthecoder/libgit2,Snazz2001/libgit2,maxiaoqian/libgit2,swisspol/DEMO-libgit2,mrksrm/Mingijura,saurabhsuniljain/libgit2,KTXSoftware/libgit2,jeffhostetler/public_libgit2,nokiddin/libgit2,mcanthony/libgit2,stewid/libgit2,raybrad/libit2,sim0629/libgit2,mhp/libgit2,yosefhackmon/libgit2,nokiddin/libgit2,oaastest/libgit2,yosefhackmon/libgit2,jeffhostetler/public_libgit2,mingyaaaa/libgit2,kissthink/libgit2,falqas/libgit2,leoyanggit/libgit2,iankronquist/libgit2,saurabhsuniljain/libgit2,raybrad/libit2,stewid/libgit2,spraints/libgit2,linquize/libgit2,since2014/libgit2,sim0629/libgit2,amyvmiwei/libgit2,skabel/manguse,whoisj/libgit2,chiayolin/libgit2,linquize/libgit2,jeffhostetler/public_libgit2,Tousiph/Demo1,sygool/libgit2,magnus98/TEST,raybrad/libit2,falqas/libgit2,mhp/libgit2,joshtriplett/libgit2,dleehr/libgit2,kissthink/libgit2,joshtriplett/libgit2,joshtriplett/libgit2,dleehr/libgit2,amyvmiwei/libgit2,yongthecoder/libgit2,mingyaaaa/libgit2,sim0629/libgit2,leoyanggit/libgit2,since2014/libgit2,Corillian/libgit2,chiayolin/libgit2,rcorre/libgit2,whoisj/libgit2,saurabhsuniljain/libgit2,stewid/libgit2,KTXSoftware/libgit2,spraints/libgit2,falqas/libgit2,t0xicCode/libgit2,chiayolin/libgit2,joshtriplett/libgit2,sygool/libgit2,jflesch/libgit2-mariadb,KTXSoftware/libgit2,swisspol/DEMO-libgit2,Snazz2001/libgit2,jflesch/libgit2-mariadb,maxiaoqian/libgit2,Tousiph/Demo1,linquize/libgit2,Corillian/libgit2,yongthecoder/libgit2,ardumont/libgit2,skabel/manguse,oaastest/libgit2,Tousiph/Demo1,falqas/libgit2,mcanthony/libgit2,oaastest/libgit2,claudelee/libgit2,linquize/libgit2,kenprice/libgit2,mcanthony/libgit2,joshtriplett/libgit2,chiayolin/libgit2,oaastest/libgit2,rcorre/libgit2,swisspol/DEMO-libgit2,leoyanggit/libgit2,magnus98/TEST,iankronquist/libgit2,nokiddin/libgit2,yongthecoder/libgit2,linquize/libgit2,Corillian/libgit2,jflesch/libgit2-mariadb,sygool/libgit2,oaastest/libgit2,mrksrm/Mingijura,skabel/manguse,oaastest/libgit2,Corillian/libgit2,jeffhostetler/public_libgit2,chiayolin/libgit2,mingyaaaa/libgit2,skabel/manguse,falqas/libgit2,skabel/manguse,yongthecoder/libgit2,amyvmiwei/libgit2,whoisj/libgit2,sim0629/libgit2,KTXSoftware/libgit2,maxiaoqian/libgit2,Corillian/libgit2,nokiddin/libgit2,stewid/libgit2,kissthink/libgit2,Snazz2001/libgit2,Snazz2001/libgit2,claudelee/libgit2,stewid/libgit2,nokiddin/libgit2,Tousiph/Demo1,kenprice/libgit2,whoisj/libgit2,KTXSoftware/libgit2,claudelee/libgit2,dleehr/libgit2,mhp/libgit2,since2014/libgit2,rcorre/libgit2,magnus98/TEST,leoyanggit/libgit2,JIghtuse/libgit2,sim0629/libgit2,yosefhackmon/libgit2,saurabhsuniljain/libgit2,raybrad/libit2,iankronquist/libgit2,spraints/libgit2,MrHacky/libgit2,t0xicCode/libgit2,Tousiph/Demo1,JIghtuse/libgit2,joshtriplett/libgit2,amyvmiwei/libgit2,JIghtuse/libgit2,chiayolin/libgit2,claudelee/libgit2,mcanthony/libgit2,magnus98/TEST,spraints/libgit2,spraints/libgit2,mcanthony/libgit2,spraints/libgit2,jflesch/libgit2-mariadb,JIghtuse/libgit2,mrksrm/Mingijura,saurabhsuniljain/libgit2,mingyaaaa/libgit2,MrHacky/libgit2,linquize/libgit2,sygool/libgit2,kenprice/libgit2,yongthecoder/libgit2,ardumont/libgit2,dleehr/libgit2,whoisj/libgit2,raybrad/libit2,MrHacky/libgit2,since2014/libgit2,kissthink/libgit2,sim0629/libgit2,kissthink/libgit2,yosefhackmon/libgit2,mingyaaaa/libgit2,mingyaaaa/libgit2,nokiddin/libgit2,amyvmiwei/libgit2,sygool/libgit2,JIghtuse/libgit2