Merge pull request swiftlang#200 from weissi/jw-SR-3628

don't hold references to unowned DispatchData objects (SR-3628)

Signed-off-by: Daniel A. Steffen <[email protected]>

Author: MadCoder

PATCHES

@@ -302,3 +302,4 @@ github commits starting with 29bdc2f from
 [eb730eb] APPLIED rdar://30568673
 [ac16fbb] APPLIED rdar://30568673
 [967876e] APPLIED rdar://30568673
+[44c2291] APPLIED rdar://30568673