revlog: rename list of nodes from "content" to "nodes"
It seems like the reason for "content" is that the variable contains
the nodes that the changegroup "contains", see
e234eda20984 (revlog:
make addgroup returns a list of node contained in the added source,
2012-01-13), but "nodes" seems much clearer.
ERROR: FIXME: This is a known failure of filelog.size for data starting with \1\n
OK.