Permit .keystone_install to perform an initial bootstrapping installation over a skeleton directory.  The skeleton is a pre-registered Keystone ticket with the correct product ID, URL, and path existence checker, and a preposterous version (like 0), in conjunction with an existing but empty .app.
Permit .keystone_install to perform an initial bootstrapping installation over
a skeleton directory.  The skeleton is a pre-registered Keystone ticket with
the correct product ID, URL, and path existence checker, and a preposterous
version (like 0), in conjunction with an existing but empty .app.

TEST=none
BUG=none
Review URL: http://codereview.chromium.org/322005

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@29890 0039d316-1c4b-4281-b951-d872f2087c98

hgl888/chromium-crosswalk,hgl888/chromium-crosswalk-efl,hujiajie/pa-chromium,zcbenz/cefode-chromium,ondra-novak/chromium.src,Jonekee/chromium.src,littlstar/chromium.src,anirudhSK/chromium,axinging/chromium-crosswalk,ltilve/chromium,Chilledheart/chromium,ChromiumWebApps/chromium,krieger-od/nwjs_chromium.src,patrickm/chromium.src,ChromiumWebApps/chromium,PeterWangIntel/chromium-crosswalk,krieger-od/nwjs_chromium.src,M4sse/chromium.src,M4sse/chromium.src,axinging/chromium-crosswalk,Fireblend/chromium-crosswalk,Just-D/chromium-1,crosswalk-project/chromium-crosswalk-efl,rogerwang/chromium,hgl888/chromium-crosswalk,nacl-webkit/chrome_deps,hgl888/chromium-crosswalk-efl,axinging/chromium-crosswalk,pozdnyakov/chromium-crosswalk,zcbenz/cefode-chromium,M4sse/chromium.src,bright-sparks/chromium-spacewalk,dednal/chromium.src,hgl888/chromium-crosswalk-efl,markYoungH/chromium.src,crosswalk-project/chromium-crosswalk-efl,zcbenz/cefode-chromium,dushu1203/chromium.src,Fireblend/chromium-crosswalk,fujunwei/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,chuan9/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,dushu1203/chromium.src,dednal/chromium.src,hujiajie/pa-chromium,zcbenz/cefode-chromium,hujiajie/pa-chromium,pozdnyakov/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,ltilve/chromium,fujunwei/chromium-crosswalk,ChromiumWebApps/chromium,robclark/chromium,crosswalk-project/chromium-crosswalk-efl,junmin-zhu/chromium-rivertrail,dushu1203/chromium.src,ltilve/chromium,rogerwang/chromium,dushu1203/chromium.src,anirudhSK/chromium,Fireblend/chromium-crosswalk,pozdnyakov/chromium-crosswalk,dednal/chromium.src,axinging/chromium-crosswalk,junmin-zhu/chromium-rivertrail,dushu1203/chromium.src,krieger-od/nwjs_chromium.src,hujiajie/pa-chromium,PeterWangIntel/chromium-crosswalk,crosswalk-project/chromium-crosswalk-efl,nacl-webkit/chrome_deps,fujunwei/chromium-crosswalk,krieger-od/nwjs_chromium.src,rogerwang/chromium,ondra-novak/chromium.src,krieger-od/nwjs_chromium.src,PeterWangIntel/chromium-crosswalk,nacl-webkit/chrome_deps,hujiajie/pa-chromium,M4sse/chromium.src,pozdnyakov/chromium-crosswalk,dushu1203/chromium.src,timopulkkinen/BubbleFish,junmin-zhu/chromium-rivertrail,ondra-novak/chromium.src,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,markYoungH/chromium.src,mohamed--abdel-maksoud/chromium.src,fujunwei/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,rogerwang/chromium,ChromiumWebApps/chromium,dednal/chromium.src,Jonekee/chromium.src,mogoweb/chromium-crosswalk,anirudhSK/chromium,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,anirudhSK/chromium,jaruba/chromium.src,littlstar/chromium.src,hujiajie/pa-chromium,M4sse/chromium.src,chuan9/chromium-crosswalk,ltilve/chromium,littlstar/chromium.src,M4sse/chromium.src,pozdnyakov/chromium-crosswalk,Pluto-tv/chromium-crosswalk,ondra-novak/chromium.src,junmin-zhu/chromium-rivertrail,nacl-webkit/chrome_deps,fujunwei/chromium-crosswalk,pozdnyakov/chromium-crosswalk,bright-sparks/chromium-spacewalk,PeterWangIntel/chromium-crosswalk,Chilledheart/chromium,pozdnyakov/chromium-crosswalk,ChromiumWebApps/chromium,chuan9/chromium-crosswalk,fujunwei/chromium-crosswalk,hujiajie/pa-chromium,rogerwang/chromium,dushu1203/chromium.src,mohamed--abdel-maksoud/chromium.src,patrickm/chromium.src,Jonekee/chromium.src,keishi/chromium,axinging/chromium-crosswalk,anirudhSK/chromium,krieger-od/nwjs_chromium.src,timopulkkinen/BubbleFish,hgl888/chromium-crosswalk-efl,Pluto-tv/chromium-crosswalk,markYoungH/chromium.src,zcbenz/cefode-chromium,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,ChromiumWebApps/chromium,chuan9/chromium-crosswalk,mogoweb/chromium-crosswalk,M4sse/chromium.src,junmin-zhu/chromium-rivertrail,dushu1203/chromium.src,junmin-zhu/chromium-rivertrail,Jonekee/chromium.src,hujiajie/pa-chromium,mogoweb/chromium-crosswalk,Jonekee/chromium.src,hujiajie/pa-chromium,keishi/chromium,TheTypoMaster/chromium-crosswalk,keishi/chromium,hgl888/chromium-crosswalk-efl,mohamed--abdel-maksoud/chromium.src,timopulkkinen/BubbleFish,robclark/chromium,anirudhSK/chromium,mogoweb/chromium-crosswalk,Fireblend/chromium-crosswalk,dushu1203/chromium.src,ChromiumWebApps/chromium,robclark/chromium,Pluto-tv/chromium-crosswalk,rogerwang/chromium,littlstar/chromium.src,nacl-webkit/chrome_deps,mohamed--abdel-maksoud/chromium.src,timopulkkinen/BubbleFish,patrickm/chromium.src,ChromiumWebApps/chromium,dednal/chromium.src,pozdnyakov/chromium-crosswalk,markYoungH/chromium.src,zcbenz/cefode-chromium,keishi/chromium,hgl888/chromium-crosswalk,keishi/chromium,M4sse/chromium.src,rogerwang/chromium,dednal/chromium.src,markYoungH/chromium.src,robclark/chromium,littlstar/chromium.src,robclark/chromium,anirudhSK/chromium,Just-D/chromium-1,Just-D/chromium-1,ondra-novak/chromium.src,mohamed--abdel-maksoud/chromium.src,jaruba/chromium.src,junmin-zhu/chromium-rivertrail,Pluto-tv/chromium-crosswalk,crosswalk-project/chromium-crosswalk-efl,ltilve/chromium,jaruba/chromium.src,zcbenz/cefode-chromium,patrickm/chromium.src,timopulkkinen/BubbleFish,bright-sparks/chromium-spacewalk,ltilve/chromium,krieger-od/nwjs_chromium.src,bright-sparks/chromium-spacewalk,hgl888/chromium-crosswalk,Jonekee/chromium.src,zcbenz/cefode-chromium,pozdnyakov/chromium-crosswalk,rogerwang/chromium,dushu1203/chromium.src,markYoungH/chromium.src,TheTypoMaster/chromium-crosswalk,ondra-novak/chromium.src,hgl888/chromium-crosswalk,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,dednal/chromium.src,anirudhSK/chromium,nacl-webkit/chrome_deps,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,junmin-zhu/chromium-rivertrail,hgl888/chromium-crosswalk-efl,Pluto-tv/chromium-crosswalk,krieger-od/nwjs_chromium.src,mohamed--abdel-maksoud/chromium.src,junmin-zhu/chromium-rivertrail,Just-D/chromium-1,krieger-od/nwjs_chromium.src,bright-sparks/chromium-spacewalk,nacl-webkit/chrome_deps,Chilledheart/chromium,hgl888/chromium-crosswalk-efl,axinging/chromium-crosswalk,littlstar/chromium.src,mogoweb/chromium-crosswalk,jaruba/chromium.src,robclark/chromium,TheTypoMaster/chromium-crosswalk,Pluto-tv/chromium-crosswalk,ltilve/chromium,crosswalk-project/chromium-crosswalk-efl,patrickm/chromium.src,Jonekee/chromium.src,ondra-novak/chromium.src,keishi/chromium,Chilledheart/chromium,jaruba/chromium.src,mogoweb/chromium-crosswalk,Fireblend/chromium-crosswalk,timopulkkinen/BubbleFish,PeterWangIntel/chromium-crosswalk,markYoungH/chromium.src,markYoungH/chromium.src,nacl-webkit/chrome_deps,Jonekee/chromium.src,ltilve/chromium,Fireblend/chromium-crosswalk,Chilledheart/chromium,patrickm/chromium.src,Just-D/chromium-1,mogoweb/chromium-crosswalk,hgl888/chromium-crosswalk-efl,markYoungH/chromium.src,zcbenz/cefode-chromium,ChromiumWebApps/chromium,chuan9/chromium-crosswalk,littlstar/chromium.src,ondra-novak/chromium.src,timopulkkinen/BubbleFish,patrickm/chromium.src,chuan9/chromium-crosswalk,hgl888/chromium-crosswalk-efl,hujiajie/pa-chromium,patrickm/chromium.src,M4sse/chromium.src,dednal/chromium.src,timopulkkinen/BubbleFish,jaruba/chromium.src,pozdnyakov/chromium-crosswalk,M4sse/chromium.src,zcbenz/cefode-chromium,dednal/chromium.src,mohamed--abdel-maksoud/chromium.src,pozdnyakov/chromium-crosswalk,keishi/chromium,nacl-webkit/chrome_deps,timopulkkinen/BubbleFish,hgl888/chromium-crosswalk,fujunwei/chromium-crosswalk,robclark/chromium,ChromiumWebApps/chromium,hujiajie/pa-chromium,TheTypoMaster/chromium-crosswalk,bright-sparks/chromium-spacewalk,jaruba/chromium.src,PeterWangIntel/chromium-crosswalk,crosswalk-project/chromium-crosswalk-efl,markYoungH/chromium.src,dushu1203/chromium.src,keishi/chromium,fujunwei/chromium-crosswalk,robclark/chromium,TheTypoMaster/chromium-crosswalk,chuan9/chromium-crosswalk,krieger-od/nwjs_chromium.src,keishi/chromium,axinging/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,nacl-webkit/chrome_deps,bright-sparks/chromium-spacewalk,patrickm/chromium.src,TheTypoMaster/chromium-crosswalk,Chilledheart/chromium,hgl888/chromium-crosswalk,nacl-webkit/chrome_deps,Jonekee/chromium.src,axinging/chromium-crosswalk,rogerwang/chromium,crosswalk-project/chromium-crosswalk-efl,Chilledheart/chromium,anirudhSK/chromium,junmin-zhu/chromium-rivertrail,axinging/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,fujunwei/chromium-crosswalk,mogoweb/chromium-crosswalk,keishi/chromium,anirudhSK/chromium,robclark/chromium,Fireblend/chromium-crosswalk,Just-D/chromium-1,jaruba/chromium.src,ltilve/chromium,ChromiumWebApps/chromium,Just-D/chromium-1,littlstar/chromium.src,jaruba/chromium.src,crosswalk-project/chromium-crosswalk-efl,mogoweb/chromium-crosswalk,Chilledheart/chromium,zcbenz/cefode-chromium,Chilledheart/chromium,timopulkkinen/BubbleFish,krieger-od/nwjs_chromium.src,keishi/chromium,dednal/chromium.src,bright-sparks/chromium-spacewalk,chuan9/chromium-crosswalk,anirudhSK/chromium,Jonekee/chromium.src,hgl888/chromium-crosswalk-efl,robclark/chromium,Fireblend/chromium-crosswalk,mogoweb/chromium-crosswalk,rogerwang/chromium,jaruba/chromium.src,markYoungH/chromium.src,dednal/chromium.src,M4sse/chromium.src,timopulkkinen/BubbleFish,jaruba/chromium.src,ChromiumWebApps/chromium,Just-D/chromium-1,anirudhSK/chromium,bright-sparks/chromium-spacewalk,Fireblend/chromium-crosswalk,junmin-zhu/chromium-rivertrail,TheTypoMaster/chromium-crosswalk,ondra-novak/chromium.src,Jonekee/chromium.src,mohamed--abdel-maksoud/chromium.src