get_identifiers can return garbage

[ghost]

In identifiers.cc, if vector get_identifiers(string var) is passed a string that doesn’t conform to what it expects, it can return garbage. In the particular case I was looking at var was “no”. Then in the loop iden.rule and iden.id are not set by the >> operator and retain an uninitialized value, which is returned in the result.

Arguably this function should print an error message if var is not of the right format, but at the least iden should be initialized.