NFC:  Rename MCSafeSEHFragment to MCSymbolIdFragment

Summary:
This fragment emits a symbol ID and will be useful for more than just Safe SEH
tables (e.g., I plan to re-use it for Control Flow Guard tables).  This is
simply a rename refactor.

Reviewers: rnk

Subscribers: llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D39770

llvm-svn: 317703
diff --git a/llvm/lib/MC/MCWinCOFFStreamer.cpp b/llvm/lib/MC/MCWinCOFFStreamer.cpp
index 7e0533b..c2583d9 100644
--- a/llvm/lib/MC/MCWinCOFFStreamer.cpp
+++ b/llvm/lib/MC/MCWinCOFFStreamer.cpp
@@ -182,7 +182,7 @@
   if (SXData->getAlignment() < 4)
     SXData->setAlignment(4);
 
-  new MCSafeSEHFragment(Symbol, SXData);
+  new MCSymbolIdFragment(Symbol, SXData);
 
   getAssembler().registerSymbol(*Symbol);
   CSymbol->setIsSafeSEH();