[product: zaphod][project: zaphod-v0.3]: Cleanup function signature.

SYNOPSIS
[modified]m42/test/zaphodtestutil.py: Change param names of execute_remote_command

DETAILS
Changed parameter name from 'server' to 'hostname' in the function
signature of zaphodtestutil.execute_remote_command. This is more
appropriate an consistent with its use in other parts of the
program.