Fix warning in util.h (signed vs unsigned comparison)
Fix warning in util.h (signed vs unsigned comparison)

This fix had been delayed by Ramsay because on 32-bit systems it
highlights the fact that off_t is set to an invalid value.

Signed-off-by: Vicent Marti <6838a7c51796da15c3e6eae80ee6aba806e8818a@gmail.com>

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