Name of a transformed STG work remains the same

[Danil Sokolov]

To reproduce:

1. Create an STG work with a basic non-dedalock specification, e.g. p0->out- -> out+ ->p0 and p0 marked.
2. Save it as a.work
3. Do Tools->Convert->Net synthesis [Petrify]

Observed behaviour:
  The produced STG is named "a" (without ".work", but still confusing)

Expected behaviour:
  Add a numerical suffix to distinguish this new work, e.g. "a 1"

Note, if the new work "a" is transformed again, then the result is called "a 1" as expected. So, the problem only appears when transforming the original "a.work".