minstall: when elevating to root, don't allow ninja to rerun

We just finished running rebuild_all, and then actually running
the install routine failed because of permission errors, so we magically
reran as root. But we should *know* that all prerequisite targets are up
to date already, we don't need to run it *again*.

Nevertheless, when running meson install directly we could end up
without --no-rebuild in the original argv. This meant that it wouldn't
be in the re-executed argv either. Add it on just in case -- repeating
it twice doesn't hurt anyway.

mesonbuild/minstall.py

@@ -560,7 +560,7 @@ class Installer:
                 print('Installation failed due to insufficient permissions.')
                 print('Attempting to use polkit to gain elevated privileges...')
                 os.execlp('pkexec', 'pkexec', sys.executable, main_file, *sys.argv[1:],
-                          '-C', os.getcwd())
+                          '-C', os.getcwd(), '--no-rebuild')
             else:
                 raise