Fix bitcode function encoding error.

BUG=5650262

This error occurred because the bitcode opcode for TYPE_CODE_FUNCTION changed
from 9 to 21 in The SVN cl mentioned below.

commit 9923d389f5a3c7817a3bd603b989ef762226ba07
Author: Chad Rosier <mcrosier@apple.com>
Date:   Thu Nov 3 00:14:01 2011 +0000

    Remove some cruft from the BitcodeWriter, while still maintaining backward
    compatibility in the BitcodeReader.

    git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143598 91177308-0d34-0410-b5e6-96231b3b80d8

Change-Id: I88ae3c65128714fbea6beb4665271c87ff552fd1
1 file changed