[Tizen] [Runtime] Fix the issue that widget apps fails to install without version attribute.
[Tizen] [Runtime] Fix the issue that widget apps fails to install without version attribute.

It reports installation crash if a widget app doesn't contains
widget 'version' attribute in the config.xml file. The root cause is
Version::GetString() always assumes a Version instance is valid, in
other words, not an empty string.

Due to the 'version' attribute could be optional for widget app, a
solution to fix this issue is we add check in
ApplicationData::VersionString().

BUG=XWALK-1226

hgl888/crosswalk,mrunalk/crosswalk,ZhengXinCN/crosswalk,chuan9/crosswalk,hgl888/crosswalk-efl,jondwillis/crosswalk,zeropool/crosswalk,amaniak/crosswalk,myroot/crosswalk,RafuCater/crosswalk,jondong/crosswalk,shaochangbin/crosswalk,stonegithubs/crosswalk,pk-sam/crosswalk,siovene/crosswalk,lincsoon/crosswalk,jpike88/crosswalk,minggangw/crosswalk,leonhsl/crosswalk,RafuCater/crosswalk,crosswalk-project/crosswalk-efl,dreamsxin/crosswalk,hgl888/crosswalk,PeterWangIntel/crosswalk,Bysmyyr/crosswalk,bestwpw/crosswalk,axinging/crosswalk,leonhsl/crosswalk,jpike88/crosswalk,XiaosongWei/crosswalk,jondong/crosswalk,weiyirong/crosswalk-1,darktears/crosswalk,hgl888/crosswalk,tomatell/crosswalk,PeterWangIntel/crosswalk,qjia7/crosswalk,crosswalk-project/crosswalk-efl,bestwpw/crosswalk,jondong/crosswalk,xzhan96/crosswalk,jondwillis/crosswalk,chinakids/crosswalk,xzhan96/crosswalk,zeropool/crosswalk,chuan9/crosswalk,tedshroyer/crosswalk,hgl888/crosswalk-efl,qjia7/crosswalk,huningxin/crosswalk,Pluto-tv/crosswalk,rakuco/crosswalk,leonhsl/crosswalk,lincsoon/crosswalk,fujunwei/crosswalk,zliang7/crosswalk,alex-zhang/crosswalk,xzhan96/crosswalk,xzhan96/crosswalk,stonegithubs/crosswalk,weiyirong/crosswalk-1,lincsoon/crosswalk,chinakids/crosswalk,rakuco/crosswalk,marcuspridham/crosswalk,TheDirtyCalvinist/spacewalk,stonegithubs/crosswalk,XiaosongWei/crosswalk,myroot/crosswalk,PeterWangIntel/crosswalk,XiaosongWei/crosswalk,chuan9/crosswalk,ZhengXinCN/crosswalk,mrunalk/crosswalk,baleboy/crosswalk,PeterWangIntel/crosswalk,baleboy/crosswalk,darktears/crosswalk,chinakids/crosswalk,siovene/crosswalk,DonnaWuDongxia/crosswalk,hgl888/crosswalk-efl,jondong/crosswalk,jondong/crosswalk,heke123/crosswalk,hgl888/crosswalk,amaniak/crosswalk,zeropool/crosswalk,crosswalk-project/crosswalk,heke123/crosswalk,Bysmyyr/crosswalk,XiaosongWei/crosswalk,zliang7/crosswalk,chuan9/crosswalk,jondong/crosswalk,siovene/crosswalk,crosswalk-project/crosswalk,alex-zhang/crosswalk,Bysmyyr/crosswalk,ZhengXinCN/crosswalk,dreamsxin/crosswalk,baleboy/crosswalk,ZhengXinCN/crosswalk,heke123/crosswalk,chinakids/crosswalk,myroot/crosswalk,XiaosongWei/crosswalk,leonhsl/crosswalk,mrunalk/crosswalk,pk-sam/crosswalk,alex-zhang/crosswalk,DonnaWuDongxia/crosswalk,pk-sam/crosswalk,darktears/crosswalk,huningxin/crosswalk,marcuspridham/crosswalk,darktears/crosswalk,DonnaWuDongxia/crosswalk,DonnaWuDongxia/crosswalk,rakuco/crosswalk,shaochangbin/crosswalk,Pluto-tv/crosswalk,heke123/crosswalk,axinging/crosswalk,Pluto-tv/crosswalk,alex-zhang/crosswalk,huningxin/crosswalk,Bysmyyr/crosswalk,rakuco/crosswalk,huningxin/crosswalk,hgl888/crosswalk,Pluto-tv/crosswalk,RafuCater/crosswalk,heke123/crosswalk,jondwillis/crosswalk,jpike88/crosswalk,TheDirtyCalvinist/spacewalk,chuan9/crosswalk,crosswalk-project/crosswalk,chuan9/crosswalk,weiyirong/crosswalk-1,myroot/crosswalk,zeropool/crosswalk,myroot/crosswalk,leonhsl/crosswalk,zliang7/crosswalk,bestwpw/crosswalk,minggangw/crosswalk,xzhan96/crosswalk,baleboy/crosswalk,alex-zhang/crosswalk,xzhan96/crosswalk,axinging/crosswalk,tedshroyer/crosswalk,chinakids/crosswalk,TheDirtyCalvinist/spacewalk,dreamsxin/crosswalk,tedshroyer/crosswalk,jondong/crosswalk,Pluto-tv/crosswalk,marcuspridham/crosswalk,minggangw/crosswalk,jpike88/crosswalk,crosswalk-project/crosswalk-efl,DonnaWuDongxia/crosswalk,stonegithubs/crosswalk,pk-sam/crosswalk,tedshroyer/crosswalk,ZhengXinCN/crosswalk,tedshroyer/crosswalk,baleboy/crosswalk,qjia7/crosswalk,xzhan96/crosswalk,zliang7/crosswalk,chinakids/crosswalk,minggangw/crosswalk,fujunwei/crosswalk,fujunwei/crosswalk,jpike88/crosswalk,hgl888/crosswalk-efl,siovene/crosswalk,mrunalk/crosswalk,crosswalk-project/crosswalk,dreamsxin/crosswalk,TheDirtyCalvinist/spacewalk,rakuco/crosswalk,darktears/crosswalk,weiyirong/crosswalk-1,lincsoon/crosswalk,tomatell/crosswalk,tomatell/crosswalk,darktears/crosswalk,baleboy/crosswalk,tedshroyer/crosswalk,pk-sam/crosswalk,bestwpw/crosswalk,darktears/crosswalk,amaniak/crosswalk,RafuCater/crosswalk,axinging/crosswalk,jondwillis/crosswalk,weiyirong/crosswalk-1,jondwillis/crosswalk,hgl888/crosswalk,lincsoon/crosswalk,bestwpw/crosswalk,dreamsxin/crosswalk,zliang7/crosswalk,PeterWangIntel/crosswalk,myroot/crosswalk,minggangw/crosswalk,tomatell/crosswalk,Bysmyyr/crosswalk,axinging/crosswalk,leonhsl/crosswalk,fujunwei/crosswalk,RafuCater/crosswalk,crosswalk-project/crosswalk,crosswalk-project/crosswalk-efl,tedshroyer/crosswalk,jondong/crosswalk,stonegithubs/crosswalk,XiaosongWei/crosswalk,minggangw/crosswalk,qjia7/crosswalk,amaniak/crosswalk,weiyirong/crosswalk-1,lincsoon/crosswalk,crosswalk-project/crosswalk,jpike88/crosswalk,RafuCater/crosswalk,pk-sam/crosswalk,zeropool/crosswalk,marcuspridham/crosswalk,Pluto-tv/crosswalk,lincsoon/crosswalk,zeropool/crosswalk,siovene/crosswalk,huningxin/crosswalk,bestwpw/crosswalk,bestwpw/crosswalk,hgl888/crosswalk-efl,lincsoon/crosswalk,marcuspridham/crosswalk,crosswalk-project/crosswalk-efl,crosswalk-project/crosswalk-efl,jondwillis/crosswalk,zliang7/crosswalk,marcuspridham/crosswalk,minggangw/crosswalk,fujunwei/crosswalk,fujunwei/crosswalk,heke123/crosswalk,baleboy/crosswalk,amaniak/crosswalk,TheDirtyCalvinist/spacewalk,tomatell/crosswalk,zliang7/crosswalk,XiaosongWei/crosswalk,tomatell/crosswalk,pk-sam/crosswalk,tomatell/crosswalk,PeterWangIntel/crosswalk,rakuco/crosswalk,axinging/crosswalk,rakuco/crosswalk,DonnaWuDongxia/crosswalk,weiyirong/crosswalk-1,RafuCater/crosswalk,heke123/crosswalk,leonhsl/crosswalk,rakuco/crosswalk,heke123/crosswalk,dreamsxin/crosswalk,siovene/crosswalk,crosswalk-project/crosswalk,fujunwei/crosswalk,TheDirtyCalvinist/spacewalk,siovene/crosswalk,qjia7/crosswalk,jpike88/crosswalk,DonnaWuDongxia/crosswalk,qjia7/crosswalk,xzhan96/crosswalk,hgl888/crosswalk,chuan9/crosswalk,ZhengXinCN/crosswalk,amaniak/crosswalk,stonegithubs/crosswalk,jondwillis/crosswalk,crosswalk-project/crosswalk,ZhengXinCN/crosswalk,Bysmyyr/crosswalk,darktears/crosswalk,dreamsxin/crosswalk,shaochangbin/crosswalk,Pluto-tv/crosswalk,marcuspridham/crosswalk,stonegithubs/crosswalk,shaochangbin/crosswalk,amaniak/crosswalk,alex-zhang/crosswalk,minggangw/crosswalk,alex-zhang/crosswalk,shaochangbin/crosswalk,shaochangbin/crosswalk,axinging/crosswalk,zliang7/crosswalk,baleboy/crosswalk,PeterWangIntel/crosswalk,marcuspridham/crosswalk,zeropool/crosswalk,Bysmyyr/crosswalk,mrunalk/crosswalk,hgl888/crosswalk-efl,huningxin/crosswalk,Bysmyyr/crosswalk,mrunalk/crosswalk,hgl888/crosswalk-efl,hgl888/crosswalk,crosswalk-project/crosswalk-efl