[origin_cartridge_200]Met "panic: runtime error: invalid memory address
or nil pointer dereference" when sti/gear build with -s option

https://bugzilla.redhat.com/show_bug.cgi?id=1105469
Merge pull request #236 from bparees/handle_invalid_url

[origin_cartridge_200]Met "panic: runtime error: invalid memory address or nil pointer dereference" when sti/gear build with -s option