ScheduleEnums: strip whitespace around the control mode strings

for some reason, the Norne deck included whitespace for some control
modes of some wells which lead to an exception. Since Eclipse seems to
eat this, and Eclipse is correct by defintion, let's adapt our
digestion system a bit...
Merge pull request #145 from andlaus/ScheduleEnums_strip_whitespace

ScheduleEnums: strip whitespace around the control mode strings