Update comment list of GLOBALVAR modifiers in BitcodeWriter to include externally_initialized.

Thanks to Shuxin Yang for catching this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192637 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 46eff4e..b082ba6 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -606,7 +606,7 @@
 
     // GLOBALVAR: [type, isconst, initid,
     //             linkage, alignment, section, visibility, threadlocal,
-    //             unnamed_addr]
+    //             unnamed_addr, externally_initialized]
     Vals.push_back(VE.getTypeID(GV->getType()));
     Vals.push_back(GV->isConstant());
     Vals.push_back(GV->isDeclaration() ? 0 :