perf db-export: Get rid of db_export__deferred()

perf db-export: Get rid of db_export__deferred()

db_export__deferred() deferred the export of comms if the comm string
had not been "set" (changed from :<pid>) however that problem was fixed
a long time ago by commit e803cf97a4f9 ("perf record: Synthesize COMM
event for a command line workload"), so get rid of
db_export__deferred().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20190710085810.1650-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>