scripts: print usage in argparse-using scripts when a command-line error occurs

For scripts that use Python's standard argparse module to parse
command-line arguments, create a subclass which will show the usage
the usage information when a command-line parsing error occurs. The most
common case would be when the script is run with no arguments; at least
then the user immediately gets to see what arguments they might need to
pass instead of just an error message.

(From OE-Core rev: d62fe7c9bc2df6a4464440a3cae0539074bf99aa)

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

scripts/devtool

@@ -37,6 +37,7 @@ lib_path = scripts_path + '/lib'
 sys.path = sys.path + [lib_path]
 from devtool import DevtoolError, setup_tinfoil
 import scriptutils
+import argparse_oe
 logger = scriptutils.logger_create('devtool')
 
 plugins = []
@@ -185,9 +186,9 @@ def main():
             break
         pth = os.path.dirname(pth)
 
-    parser = argparse.ArgumentParser(description="OpenEmbedded development tool",
-                                     add_help=False,
-                                     epilog="Use %(prog)s <subcommand> --help to get help on a specific command")
+    parser = argparse_oe.ArgumentParser(description="OpenEmbedded development tool",
+                                        add_help=False,
+                                        epilog="Use %(prog)s <subcommand> --help to get help on a specific command")
     parser.add_argument('--basepath', help='Base directory of SDK / build directory')
     parser.add_argument('--bbpath', help='Explicitly specify the BBPATH, rather than getting it from the metadata')
     parser.add_argument('-d', '--debug', help='Enable debug output', action='store_true')