BUGFIX: Integer argumentName should not result in an exception
BUGFIX: Integer argumentName should not result in an exception

This prevents an exception in case an argument name is evaluated to
another simple type (integer) but can be converted to string easily.

Fixes: #612

dlubitz/flow-development-collection,gerhard-boden/flow-development-collection,fcool/flow-development-collection,aertmann/flow-development-collection,neos/flow-development-collection,aertmann/flow-development-collection,robertlemke/flow-development-collection,fcool/flow-development-collection,dlubitz/flow-development-collection,robertlemke/flow-development-collection,bwaidelich/flow-development-collection,daniellienert/flow-development-collection,neos/flow-development-collection,bwaidelich/flow-development-collection,kdambekalns/flow-development-collection,daniellienert/flow-development-collection,gerhard-boden/flow-development-collection,albe/flow-development-collection,kdambekalns/flow-development-collection,aertmann/flow-development-collection,neos/flow-development-collection,fcool/flow-development-collection,albe/flow-development-collection,dlubitz/flow-development-collection,gerhard-boden/flow-development-collection,robertlemke/flow-development-collection,kdambekalns/flow-development-collection,bwaidelich/flow-development-collection,neos/flow-development-collection,albe/flow-development-collection,kdambekalns/flow-development-collection,daniellienert/flow-development-collection,robertlemke/flow-development-collection,fcool/flow-development-collection