Fix implicit ios -> watchOS availability version mapping for
versions that have the major number only

rdar://48018651

llvm-svn: 356605
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index f16b6e9..e8a77b3 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -2508,6 +2508,7 @@
               else
                 return VersionTuple(NewMajor, Version.getMinor().getValue());
             }
+            return VersionTuple(NewMajor);
           }
 
           return VersionTuple(2, 0);