cmake: Fix 'examples' target after r225319
cmake: Fix 'examples' target after r225319

Add the missing `DEPENDS` keyword.  r225319 did almost the right thing
(I didn't notice the problem with it because `Kaleidoscope-Ch8` wasn't
building at all).

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@225321 91177308-0d34-0410-b5e6-96231b3b80d8

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