[modules] When a MacroInfo object is deserialized, allocate and store its submodule ID.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@177760 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/MacroInfo.cpp b/lib/Lex/MacroInfo.cpp
index 3d4ffb4..213e711 100644
--- a/lib/Lex/MacroInfo.cpp
+++ b/lib/Lex/MacroInfo.cpp
@@ -28,7 +28,8 @@
     IsDisabled(false),
     IsUsed(false),
     IsAllowRedefinitionsWithoutWarning(false),
-    IsWarnIfUnused(false) {
+    IsWarnIfUnused(false),
+    FromASTFile(false) {
 }
 
 unsigned MacroInfo::getDefinitionLengthSlow(SourceManager &SM) const {