mew's install-info invocations are not failsafe against excludedocs or
read-only-netsharedpath-/usr/share installations; appending "|| :" to the
invocations in %post and %preun would fix it.

Additionally, the (Pre)Requires(foo,bar) syntax is known to be broken in many
versions of rpm, and in this case, the /sbin/install-info erase time dependency
should be preun, not postun.  So "Prereq(post,postun): /sbin/install-info"
should be split to two and replaced by "Requires(post): /sbin/install-info" and
"Requires(postun): /sbin/install-info".

More info: http://fedoraproject.org/wiki/Packaging/ScriptletSnippets