Entering properties into the Properties() object can be error prone. Add some preliminary checks of property keys before writing file.

da Silva Unfortunately Rajiv and I had already looked at ENUMS (and other options) but that can be problematic for the following properties where the key itself is dynamic.

pegasus.file.cleanup.constraint.*.maxspace
pegasus.log.*
pegasus.transfer.*.remote.sites
pegasus.transfer.*.impl
pegasus.selector.site.env.*
pegasus.selector.regex.rank.*
pegasus.selector.replica.*.prefer.stagein.sites
pegasus.selector.replica.*.ignore.stagein.sites
pegasus.catalog.replica.output.*
pegasus.catalog.*.timeout
pegasus.catalog..db.
pegasus.catalog.*.db.password
pegasus.catalog.*.db.user
pegasus.catalog.*.db.url
pegasus.catalog.*.db.driver
dagman.*.maxjobs
env.*
dagman.*
condor.*
globus.*

With that said, it will be straightforward for me to still validate the keys (including the variable ones to some extent).