Merging r353907:

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r353907 | rnk | 2019-02-13 02:39:32 +0100 (Wed, 13 Feb 2019) | 6 lines

[MC] Make symbol version errors non-fatal

We stil don't have a source location, which is pretty lame, but at least
we won't tell the user to file a clang bug report anymore.

Fixes PR40712
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llvm-svn: 354257