Ascent guidance doesn't like having Mammoth as first stage

[rsparkyc]

Testing this with RSS installed (working on building a RP-0 installation) on 1.4.3 with build 800. Here's the exception:

MechJeb module MechJebModuleAscentAutopilot threw an exception in Drive: System.ArgumentOutOfRangeException: Argument is out of range.
Parameter name: index
  at System.Collections.Generic.List`1[MuMech.MechJebModuleAscentPEG+StageInfo].get_Item (Int32 index) [0x00000] in <filename unknown>:0
  at MuMech.MechJebModuleAscentPEG.UpdateRocketStats () [0x00000] in <filename unknown>:0
  at MuMech.MechJebModuleAscentPEG.DriveAscent (.FlightCtrlState s) [0x00000] in <filename unknown>:0
  at MuMech.MechJebModuleAscentAutopilot.DriveAscent (.FlightCtrlState s) [0x00000] in <filename unknown>:0
  at MuMech.MechJebModuleAscentAutopilot.Drive (.FlightCtrlState s) [0x00000] in <filename unknown>:0
  at MuMech.MechJebCore.Drive (.FlightCtrlState s) [0x00000] in <filename unknown>:0

[rsparkyc]

I can confirm this is an issue when playing just stock + mechjeb

[rsparkyc]

Actually, it looks like my number of stages may have been set to more than the rocket had, perhaps that's what was throwing the exception

[lamont-granquist]

https://github.com/lamont-granquist/MechJeb2/releases doesn't have num_stages (and generally the now-old PEG code in MJ release is going to get replaced rather than fixed)

[rsparkyc]

Ahh, didn't realize you were doing mechjeb builds @lamont-granquist. Seeing how many of the most recent PRs have been from you, I suppose I can assume your builds will be more up to date than this this repo.