Fix warning converting from boolean to pointer introduced in r301153.

This reverts commit r301155, which was incorrect.

llvm-svn: 301156

llvm/lib/Support/DynamicLibrary.cpp

@@ -61,7 +61,7 @@ public:
       Handles.push_back(Handle);
     } else {
 #ifndef LLVM_ON_WIN32
-      if (Process != nullptr) {
+      if (Process) {
         if (CanClose)
           DLClose(Process);
         if (Process == Handle)

llvm/lib/Support/Windows/DynamicLibrary.inc

@@ -61,7 +61,7 @@ void *DynamicLibrary::HandleSet::DLOpen(const char *File, std::string *Err) {
 
 static DynamicLibrary::HandleSet *IsOpenedHandlesInstance(void *Handle) {
   if (!OpenedHandles.isConstructed())
-    return false;
+    return nullptr;
   DynamicLibrary::HandleSet &Inst = *OpenedHandles;
   return Handle == &Inst ? &Inst : nullptr;
 }