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.
#
# Avoid interference from actual test env:
unset HGTEST_JOBS
unset HGTEST_TIMEOUT
unset HGTEST_PORT
unset HGTEST_SHELL