Removed explicit NULL checks for shared pointers
and instead made us use implicit casts to bool.
This generated a warning in C++11.

<rdar://problem/11930775>

llvm-svn: 161559
diff --git a/lldb/source/Expression/ClangExpressionParser.cpp b/lldb/source/Expression/ClangExpressionParser.cpp
index 22fae91..88e7323 100644
--- a/lldb/source/Expression/ClangExpressionParser.cpp
+++ b/lldb/source/Expression/ClangExpressionParser.cpp
@@ -756,7 +756,7 @@
     
     lldb::DisassemblerSP disassembler = Disassembler::FindPlugin(arch, NULL);
     
-    if (disassembler == NULL)
+    if (!disassembler)
     {
         ret.SetErrorToGenericError();
         ret.SetErrorStringWithFormat("Unable to find disassembler plug-in for %s architecture.", arch.GetArchitectureName());