devtool: un-globalize 'plugins' variable

It never had to be a global anyway

(From OE-Core rev: 2d5557f4f5d228e94bc7a55ae5fd72b70b5c93e4)

Signed-off-by: Chris Laplante <chris.laplante@agilent.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/devtool

@@ -28,8 +28,6 @@ import scriptutils
 import argparse_oe
 logger = scriptutils.logger_create('devtool')
 
-plugins = []
-
 
 class ConfigHandler:
     basepath = None
@@ -302,6 +300,7 @@ def main():
 
     context = Context(fixed_setup=is_fixed_setup, config=config, pluginpaths=pluginpaths)
 
+    plugins = []
     for pluginpath in pluginpaths:
         scriptutils.load_plugins(logger, plugins, pluginpath)