devtool: prevent BBHandledException from showing traceback

If we don't catch this then attempting to run devtool in non-memres mode
when bitbake is already running will produce a traceback instead of just
an error message.

(From OE-Core rev: e01b75dff599ffa2b66e6608b28bbb3564365eee)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/devtool

@@ -288,11 +288,14 @@ def main():
     scriptutils.logger_setup_color(logger, global_args.color)
 
     if global_args.bbpath is None:
-        tinfoil = setup_tinfoil(config_only=True, basepath=basepath)
         try:
-            global_args.bbpath = tinfoil.config_data.getVar('BBPATH', True)
-        finally:
-            tinfoil.shutdown()
+            tinfoil = setup_tinfoil(config_only=True, basepath=basepath)
+            try:
+                global_args.bbpath = tinfoil.config_data.getVar('BBPATH', True)
+            finally:
+                tinfoil.shutdown()
+        except bb.BBHandledException:
+            return 2
 
     # Search BBPATH first to allow layers to override plugins in scripts_path
     for path in global_args.bbpath.split(':') + [scripts_path]: