[lldb] NFC: Remove the extra ';'

Summary:
Remove extra `;` to eliminate the following pedantic warning.

```
warning: extra ';' [-Wpedantic]

```

Reviewers: shafik

Reviewed By: shafik

Subscribers: abidh, lldb-commits

Differential Revision: https://reviews.llvm.org/D54528

llvm-svn: 347047

lldb/source/Plugins/Language/CPlusPlus/LibCxxVariant.cpp

@@ -111,7 +111,7 @@ ValueObjectSP LibcxxVariantGetNthHead(ValueObjectSP &impl_sp, uint64_t index) {
   }
 
   return current_level->GetChildMemberWithName(ConstString("__head"), true);
-};
+}
 } // namespace
 
 namespace lldb_private {