Restriction on length of fuel_version removed

500 error raised in case of cluster created with fuel_version length
greater than 30. Restriction on length of field fuel_version removed
from DB. Text type used instead String(30)

Change-Id: I163b276aed5aa08cfee494751a22682512128060
Closes-Bug: #1316154
Merge "Restriction on length of fuel_version removed"