localrepo: fix bugs in branchheads and add docstring
- The call to reverse() reversed the list in place in the global branchmap.
- The nodesbetween function doesn't preserve ordering.
convert: fix marshalling in P4 convert extension to use a binary stream
The Perforce convert extension uses the p4 -G command line option and
marshal.load to obtain information about the history of a Perforce depot.
The method marshal.load must be provided with a binary stream (mode='rb') in
order to function reliably. Certain changelist descriptions or other elements
in a depot history could trigger a premature EOFError, causing the conversion
process to fail.
This may resolve the issue discussed in the following thread:
http://www.selenic.com/pipermail/mercurial/2009-July/026813.html