macOS: Fix signing issues with notarization

Notarization requires signing with hardened runtime, but this added
requirements to the additional plugins we copy into Qt Creator for the
commercial package.

This patch fixes an issue with an absolute RPATH still being left in
extra plugins, and avoids copying plugins into an already signed
application by not signing the 7zips, but only the contents in the open
source disk image (and the installers are signed by the installer jobs
anyhow).

Change-Id: I8c945a0ad9df610b20a8ee110320875f255c65b4
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

scripts/createDistPackage.py

@@ -33,8 +33,7 @@ import tempfile
 import common
 
 def parse_arguments():
-    parser = argparse.ArgumentParser(description="Create Qt Creator package, filtering out debug information files.",
-        epilog="To sign the contents before packaging on macOS, set the SIGNING_IDENTITY and optionally the SIGNING_FLAGS environment variables.")
+    parser = argparse.ArgumentParser(description="Create Qt Creator package, filtering out debug information files.")
     parser.add_argument('--7z', help='path to 7z binary',
         default='7z.exe' if common.is_windows_platform() else '7z',
         metavar='<7z_binary>', dest='sevenzip')
@@ -53,9 +52,6 @@ def main():
     try:
         common.copytree(arguments.source_directory, tempdir, symlinks=True,
             ignore=(common.is_not_debug if arguments.debug else common.is_debug))
-        # on macOS we might have to codesign (again) to account for removed debug info
-        if not arguments.debug:
-            common.codesign(tempdir)
         # package
         zip_source = os.path.join(tempdir, '*') if arguments.exclude_toplevel else tempdir
         subprocess.check_call([arguments.sevenzip, 'a', '-mmt2',