Fix bug in checksum reporting

The number of variables in the string printed for a checksum failure
was not correct. Now a useful error message is printed instead of a
stack trace and a TypeError.
Merge pull request #10 in SCALE/spack from ~SHRADER3/spack:develop to develop

# By David Shrader
# Via David Shrader
* commit '1c1e7295f02b123310efe88b0a23a9cb95cce2f4':
  Fix bug in checksum reporting
Preliminary SAMRAI package
Added tmux and supporting packages (ncurses and libevent)
Package builds and installs SAMRAI and deps with GNU and OpenMPI
Added package for vim
Merge pull request #13 in SCALE/spack from features/vim to develop

# By David Beckingsale
# Via David Beckingsale
* commit '2cb06155a7c5767accc0f6027b4805c9ab459bd4':
  Added package for vim
Merge pull request #12 in SCALE/spack from features/samrai to develop

# By David Beckingsale (1) and Todd Gamblin (1)
# Via David Beckingsale
* commit '2632bd97459e48404fe3fad0695219bf5bbb6f3f':
  Package builds and installs SAMRAI and deps with GNU and OpenMPI
  Preliminary SAMRAI package
Merge pull request #11 in SCALE/spack from features/tmux to develop

# By David Beckingsale
# Via David Beckingsale
* commit 'e402a2e27cc2942a20916615c8eb06999c0320e6':
  Added tmux and supporting packages (ncurses and libevent)