[CHEF-5163] Support lazy evaluation the mount resource's options attr

set_or_return calls #call on any DelayedEvaluator on read and compares
the results against the parameter validations. This patch adds String
to the evaluation but ensure that someone reading the options value
will only ever get an Array, keeping the original contract.
Contribution information for CHEF-5163.
Turn off server related gems during travis run.
Merge pull request #1366 from opscode/ssd/CHEF-5163-chef10

[CHEF-5163] Support lazy evaluation the mount resource's options attr