Similar to commit 52dbeac8, we should indent code snippets in
other places to ensure they appear correctly in html.  See
http://libvirt.org/html/libvirt-libvirt.html#virNodeGetCPUStats
for an example improved by this patch.  Also fix some missing
semicolons in the examples.

* src/libvirt.c: Indent code samples in comments.
Signed-off-by: NEric Blake <eblake@redhat.com>