perf scripts python: export-to-sqlite.py: Fix DROP VIEW power_events_view

Drop power_events_view before its dependent tables.

SQLite does not seem to mind but the fix was needed for PostgreSQL
(export-to-postgresql.py script), so do the same fix for the SQLite. It is
more logical and keeps the 2 scripts following the same approach.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Fixes: 5130c6e5

 ("perf scripts python: export-to-sqlite.py: Export Intel PT power and ptwrite events")
Link: http://lkml.kernel.org/r/20190708055232.5032-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>