DOC: fix typo in the body parser documentation for msg.sov

"positive" ... "null or positive". The second one is "null or negative".
BUG/MEDIUM: pattern: don't load more than once a pattern list.

A memory optimization can use the same pattern expression for many
equal pattern list (same parse method, index method and index_smp
method).

The pattern expression is returned by "pattern_new_expr", but this
function dont indicate if the returned pattern is already in use.

So, the caller function reload the list of patterns in addition with
the existing patterns. This behavior is not a problem with tree indexed
pattern, but it grows the lists indexed patterns.

This fix add a "reuse" flag in return of the function "pattern_new_expr".
If the flag is set, I suppose that the patterns are already loaded.

This fix must be backported into 1.5.
BUG/MINOR: peers: the buffer size is global.tune.bufsize, not trash.size

Currently this is harmless since trash.size is copied from
global.tune.bufsize, but this may soon change when buffers become
more dynamic.

At least for consistency it should be backported to 1.5.