Tidy the calls to getCurrentSection().first -> getCurrentSectionOnly to help
readability a bit.

llvm-svn: 284202
diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 124a191..e0b5310 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -292,7 +292,7 @@
 
 void MCStreamer::EmitLabel(MCSymbol *Symbol) {
   assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
-  assert(getCurrentSection().first && "Cannot emit before setting section!");
+  assert(getCurrentSectionOnly() && "Cannot emit before setting section!");
   assert(!Symbol->getFragment() && "Unexpected fragment on symbol data!");
   Symbol->setFragment(&getCurrentSectionOnly()->getDummyFragment());