remote: don't try to update FETCH_HEAD if no extra heads exist
remote: don't try to update FETCH_HEAD if no extra heads exist

Don't try to update anything if there are no heads to update. This
saves us from trying to look into a fetch refspec when there is none.

A better fix for compatibility with git when using remotes without
refspecs is still needed, but this stops us from segfaulting.

linquize/libgit2,KTXSoftware/libgit2,leoyanggit/libgit2,dleehr/libgit2,mingyaaaa/libgit2,magnus98/TEST,linquize/libgit2,jamieleecool/ptest,t0xicCode/libgit2,sim0629/libgit2,yongthecoder/libgit2,falqas/libgit2,claudelee/libgit2,kissthink/libgit2,mrksrm/Mingijura,nokiddin/libgit2,Snazz2001/libgit2,jamieleecool/ptest,nokiddin/libgit2,kissthink/libgit2,swisspol/DEMO-libgit2,falqas/libgit2,amyvmiwei/libgit2,jeffhostetler/public_libgit2,mcanthony/libgit2,iankronquist/libgit2,chiayolin/libgit2,maxiaoqian/libgit2,mhp/libgit2,ardumont/libgit2,sygool/libgit2,yongthecoder/libgit2,evhan/libgit2,JIghtuse/libgit2,mingyaaaa/libgit2,since2014/libgit2,claudelee/libgit2,JIghtuse/libgit2,yongthecoder/libgit2,whoisj/libgit2,yosefhackmon/libgit2,mhp/libgit2,t0xicCode/libgit2,Snazz2001/libgit2,yosefhackmon/libgit2,kenprice/libgit2,dleehr/libgit2,yongthecoder/libgit2,zodiac/libgit2.js,mcanthony/libgit2,jamieleecool/ptest,mrksrm/Mingijura,mhp/libgit2,t0xicCode/libgit2,mrksrm/Mingijura,Aorjoa/libgit2_maked_lib,MrHacky/libgit2,yosefhackmon/libgit2,stewid/libgit2,since2014/libgit2,claudelee/libgit2,sim0629/libgit2,KTXSoftware/libgit2,sim0629/libgit2,ardumont/libgit2,amyvmiwei/libgit2,leoyanggit/libgit2,jeffhostetler/public_libgit2,rcorre/libgit2,saurabhsuniljain/libgit2,claudelee/libgit2,swisspol/DEMO-libgit2,t0xicCode/libgit2,KTXSoftware/libgit2,kissthink/libgit2,mcanthony/libgit2,sim0629/libgit2,chiayolin/libgit2,Snazz2001/libgit2,chiayolin/libgit2,leoyanggit/libgit2,mrksrm/Mingijura,whoisj/libgit2,Snazz2001/libgit2,nokiddin/libgit2,whoisj/libgit2,yongthecoder/libgit2,jamieleecool/ptest,JIghtuse/libgit2,skabel/manguse,swisspol/DEMO-libgit2,jeffhostetler/public_libgit2,MrHacky/libgit2,kenprice/libgit2,KTXSoftware/libgit2,mingyaaaa/libgit2,ardumont/libgit2,jflesch/libgit2-mariadb,sygool/libgit2,sygool/libgit2,whoisj/libgit2,spraints/libgit2,whoisj/libgit2,t0xicCode/libgit2,rcorre/libgit2,nokiddin/libgit2,mrksrm/Mingijura,sygool/libgit2,linquize/libgit2,swisspol/DEMO-libgit2,jflesch/libgit2-mariadb,swisspol/DEMO-libgit2,zodiac/libgit2.js,falqas/libgit2,falqas/libgit2,raybrad/libit2,skabel/manguse,sim0629/libgit2,since2014/libgit2,Corillian/libgit2,swisspol/DEMO-libgit2,jeffhostetler/public_libgit2,amyvmiwei/libgit2,mrksrm/Mingijura,iankronquist/libgit2,nokiddin/libgit2,chiayolin/libgit2,since2014/libgit2,mingyaaaa/libgit2,Corillian/libgit2,Snazz2001/libgit2,evhan/libgit2,magnus98/TEST,joshtriplett/libgit2,rcorre/libgit2,mingyaaaa/libgit2,raybrad/libit2,magnus98/TEST,MrHacky/libgit2,mhp/libgit2,kenprice/libgit2,iankronquist/libgit2,skabel/manguse,JIghtuse/libgit2,Corillian/libgit2,rcorre/libgit2,joshtriplett/libgit2,kenprice/libgit2,ardumont/libgit2,iankronquist/libgit2,Aorjoa/libgit2_maked_lib,dleehr/libgit2,Tousiph/Demo1,yosefhackmon/libgit2,Aorjoa/libgit2_maked_lib,sim0629/libgit2,claudelee/libgit2,Corillian/libgit2,Tousiph/Demo1,since2014/libgit2,ardumont/libgit2,maxiaoqian/libgit2,dleehr/libgit2,jeffhostetler/public_libgit2,leoyanggit/libgit2,zodiac/libgit2.js,mcanthony/libgit2,mingyaaaa/libgit2,mhp/libgit2,spraints/libgit2,falqas/libgit2,joshtriplett/libgit2,Tousiph/Demo1,oaastest/libgit2,saurabhsuniljain/libgit2,kissthink/libgit2,saurabhsuniljain/libgit2,skabel/manguse,jflesch/libgit2-mariadb,oaastest/libgit2,dleehr/libgit2,since2014/libgit2,falqas/libgit2,amyvmiwei/libgit2,saurabhsuniljain/libgit2,whoisj/libgit2,joshtriplett/libgit2,MrHacky/libgit2,linquize/libgit2,JIghtuse/libgit2,raybrad/libit2,sygool/libgit2,yosefhackmon/libgit2,MrHacky/libgit2,KTXSoftware/libgit2,oaastest/libgit2,maxiaoqian/libgit2,stewid/libgit2,evhan/libgit2,joshtriplett/libgit2,leoyanggit/libgit2,spraints/libgit2,jflesch/libgit2-mariadb,Snazz2001/libgit2,iankronquist/libgit2,yongthecoder/libgit2,Aorjoa/libgit2_maked_lib,kenprice/libgit2,chiayolin/libgit2,oaastest/libgit2,linquize/libgit2,KTXSoftware/libgit2,rcorre/libgit2,zodiac/libgit2.js,stewid/libgit2,kenprice/libgit2,chiayolin/libgit2,skabel/manguse,kissthink/libgit2,oaastest/libgit2,mcanthony/libgit2,spraints/libgit2,Corillian/libgit2,rcorre/libgit2,amyvmiwei/libgit2,t0xicCode/libgit2,Aorjoa/libgit2_maked_lib,leoyanggit/libgit2,jflesch/libgit2-mariadb,stewid/libgit2,amyvmiwei/libgit2,ardumont/libgit2,saurabhsuniljain/libgit2,JIghtuse/libgit2,magnus98/TEST,stewid/libgit2,MrHacky/libgit2,oaastest/libgit2,maxiaoqian/libgit2,Corillian/libgit2,mhp/libgit2,Tousiph/Demo1,dleehr/libgit2,magnus98/TEST,saurabhsuniljain/libgit2,Tousiph/Demo1,evhan/libgit2,sygool/libgit2,nokiddin/libgit2,joshtriplett/libgit2,claudelee/libgit2,linquize/libgit2,jeffhostetler/public_libgit2,iankronquist/libgit2,raybrad/libit2,maxiaoqian/libgit2,skabel/manguse,stewid/libgit2,kissthink/libgit2,Tousiph/Demo1,maxiaoqian/libgit2,spraints/libgit2,zodiac/libgit2.js,jflesch/libgit2-mariadb,spraints/libgit2,raybrad/libit2,yosefhackmon/libgit2,mcanthony/libgit2,magnus98/TEST