sdk.py: Fix undefined variable

"sdk_update" uses a variable newsdk_path, which was never declared.
This would cause the command:

    devtool sdk-update <poky-sdk-latest>

to fail with an error:
NameError: global name 'newsdk_path' is not defined

The remedy is to declare newsdk_path as it was no doubt intended,
corresponding to the argument specifying <poky-sdk-latest>.

[YOCTO#9042]

(From OE-Core rev: 6ac589a4a9290665f8c5295e2e2a03a2b187b957)

Signed-off-by: Juro Bystricky <juro.bystricky@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/devtool/sdk.py

@@ -133,6 +133,7 @@ def sdk_update(args, config, basepath, workspace):
             logger.debug("Found conf/locked-sigs.inc in %s" % updateserver)
         update_dict = generate_update_dict(new_locked_sig_file_path, old_locked_sig_file_path)
         logger.debug("update_dict = %s" % update_dict)
+        newsdk_path = updateserver
         sstate_dir = os.path.join(newsdk_path, 'sstate-cache')
         if not os.path.exists(sstate_dir):
             logger.error("sstate-cache directory not found under %s" % newsdk_path)