Add needed Clear methods.
<rdar://problem/10596340>


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@146902 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/source/API/SBValue.cpp b/source/API/SBValue.cpp
index daaeea0..876670a 100644
--- a/source/API/SBValue.cpp
+++ b/source/API/SBValue.cpp
@@ -75,6 +75,12 @@
     return m_opaque_sp.get() != NULL;
 }
 
+void
+SBValue::Clear()
+{
+    m_opaque_sp.reset();
+}
+
 SBError
 SBValue::GetError()
 {