Comment 7 for bug 1393557

I have found the second workaround:
to add current folder to my PATH variable.

$ export PATH=$PATH:.

$ ./launch.sh
Checking for 'expect'... OK
If you run this script under Cygwin, you may have to add path to VirtualBox directory to your PATH.
Usually it is enough to run "export PATH=$PATH:"/cygdrive/c/Program Files/Oracle/VirtualBox"
Checking for "VBoxManage"... OK
Checking for VirtualBox Extension Pack... OK
Checking for Mirantis OpenStack ISO image... OK
Going to use Mirantis OpenStack ISO file iso/MirantisOpenStack-5.1.iso
Checking if SSH client installed...
OK
Checking if ipconfig or ifconfig installed...
OK
Setup is done.
Found existing VM: fuel-master. Deleting it...
Deleting existing virtual machine fuel-master...
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%

But this approach is not recommended because it adds security vulnerability
as discussed here:
http://stackoverflow.com/questions/6331075/why-do-you-need-dot-slash-before-script-name-to-run-it-in-bash

We should be able to reproduce the "iso image not found " issue on Unix as well,
if PATH variable does not contain current folder.