Bug#588575: SLIME and Swank have version mismatch

[Milan Zamazal]

The problem seems to be here:

  (defvar slime-protocol-version nil)
  (setq slime-protocol-version
        (eval-when-compile (slime-changelog-date)))

When new slime version gets installed before cl-swank, it stores the old
cl-swank version into slime-protocol-version.  I don't know why
eval-when-compile is used there, I should probably ask upstream.