[patch] Fixed a typo in distfetch.c

[git_johnko.ca]

Summary

Forgive me if this is not the right place to submit a patch.

I fixed a typographical error from "Could could change to directory..." to "Could not change to directory..."

[git_johnko.ca]

Decided to omit the addition of the copyright year and my name for a simple fix.

[git_johnko.ca]

Trying to get the "Browse in Diffusion" to work.

[dteske]

Looks good. Thank you very much. Will commit with kudos.

[dteske]

Will MFC to stable/10 and stable/9 in 3 days

[dteske]

committed to HEAD: https://svnweb.freebsd.org/base?view=revision&revision=290340