marvin: use a low sized iso for deploy by iso tests
marvin: use a low sized iso for deploy by iso tests

The currently used iso is very large (4GB) and can lead to download issues,
or slow responses. With this fix a very small iso is used for performing
deploy vm using iso related tests.

Signed-off-by: Rohit Yadav <902b9eb5dd62819678163bd5e00fbf0cbc7c264b@shapeblue.com>

shapeblue/Trillian,shapeblue/Trillian,shapeblue/Trillian