Changes

pySim-shell_test/utils: delete log files in general

When we get rid of temporary files, we delete those using a wildcard,
but for the logs from pySim-shell we explicitly memorize the name
of the pySim-shell logfile and delete it later by this explicit
name. This is not necessary, let's just delete all log files present
using a wildcard.

Related: OS#6601
Change-Id: I09dc7e59d1a3dcb68f54e3a8dccb86a1bc6c9ee6