BUG: fix manpage example code

[valoq]

Fix for #57

[pcmoore]

Thanks for the patches, I'll take a closer look at them, but could you please add your sign-off? You can find more information in the SUBMITTING_PATCHES file:

• https://github.com/seccomp/libseccomp/blob/master/SUBMITTING_PATCHES

Also, why did you include commit 070bf42 in this PR? It isn't a test and it isn't likely to be viewed by someone looking at the manpage.

[valoq]

Also, why did you include commit 070bf42 in this PR? It isn't a test and it isn't likely to be viewed by someone looking at the manpage.

My mistake, sorry.
All fixed now.

[pcmoore]

Thanks, merged via f6a4e74.