Escape spaces in stubs for uninstallation

[felipecrs]

I noticed this problem when trying to uninstall Python:

Obviously, the source problem is something else that should be fixed. But nevertheless, the stubs should be protected. There may exist some real program name with spaces as well, for example.

Before

After

[felipecrs]

The -f prevents errors like these:

$ pkgx uninstall jfrog
rm: cannot remove 'jf': No such file or directory