scripts/oe-check-sstate: cleanup

The scriptutils import isn't used, there's no need to run bitbake
in a shell environment, and invoke bitbake as a list instead of a
string.

(From OE-Core rev: 4b9946bd3961679048e1460bdfc74b286c386feb)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 663aa284adf312eb5c8a471e5dbff2634e87897d)
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/oe-check-sstate

@@ -18,7 +18,6 @@ import re
 scripts_path = os.path.dirname(os.path.realpath(__file__))
 lib_path = scripts_path + '/lib'
 sys.path = sys.path + [lib_path]
-import scriptutils
 import scriptpath
 scriptpath.add_bitbake_lib_path()
 import argparse_oe
@@ -51,11 +50,8 @@ def check(args):
             env['TMPDIR:forcevariable'] = tmpdir
 
         try:
-            output = subprocess.check_output(
-                    'bitbake -n %s' % ' '.join(args.target),
-                    stderr=subprocess.STDOUT,
-                    env=env,
-                    shell=True)
+            cmd = ['bitbake', '--dry-run'] + args.target
+            output = subprocess.check_output(cmd, stderr=subprocess.STDOUT, env=env)
 
             task_re = re.compile('NOTE: Running setscene task [0-9]+ of [0-9]+ \(([^)]+)\)')
             tasks = []