patchbomb: extract 'getpatches' closure in its own function Keep marching toward the promised land of simplification!

patchbomb: extract 'getoutgoing' closure into its own function The patchbomb command is a gigantic 300 line function full of closures. As a first step to simplify it in smaller bits, I'm extracting the closures into full featured functions. The first victim is 'getoutgoing'. It gains a docstring in the process.

bundle2: handle empty 'b2x:changegroup' value in push and pull Changeset e4dc2b0be056 added advertising of supported changegroup version through the new 'b2x:changegroup' capability. However, this capability is not new and has been around since 3.1 with an empty value. This makes new clients unable to push to 3.2 servers through bundle2 as they cannot find a common changegroup version to use from and empty list. Treating empty 'b2x:changegroup' value as old client fixes it.

bundle2: drop duplicated definition of 'b2x:exchange' This bundle2 capability is going to be dynamically computed in 'getrepocaps'. We do not need to include it in the static value.

convert: use git diff-tree -Cn% instead of --find-copies=n% for older git The option --find-copies was added in a later git version than the one included in Debian squeeze-lts (1.7.2.5), probably around 1.7.4.

changelog: rely on transaction for finalization Instead of calling 'cl.finalize()' by hand (possibly at a bogus time) we register it in the transaction during 'delayupdate' and rely on 'tr.close()' to call it at the right time.