west: _bootstrap: clean up bootstrapping exceptions

Calling bootstrap() from the WestNotFound exception handler in init()
is making the WestNotFound show up in stack traces for errors in
bootstrap(), which makes for confusing output. Fix that by moving the
call to bootstrap() out.

Signed-off-by: Marti Bolivar <marti@foundries.io>

src/west/_bootstrap/main.py

@@ -171,7 +171,11 @@ to handle any resetting yourself.
 
     try:
         reinit(os.path.join(west_dir(args.directory), 'config'), args)
+        bootstrapping = False
     except WestNotFound:
+        bootstrapping = True
+
+    if bootstrapping:
         bootstrap(args)