Remove UUID::SetFromCString

Replace uses with SetFromStringRef. NFC.

llvm-svn: 335246
diff --git a/lldb/source/Interpreter/OptionValueUUID.cpp b/lldb/source/Interpreter/OptionValueUUID.cpp
index 07c739d..b5c6600 100644
--- a/lldb/source/Interpreter/OptionValueUUID.cpp
+++ b/lldb/source/Interpreter/OptionValueUUID.cpp
@@ -43,7 +43,7 @@
 
   case eVarSetOperationReplace:
   case eVarSetOperationAssign: {
-    if (m_uuid.SetFromCString(value.str().c_str()) == 0)
+    if (m_uuid.SetFromStringRef(value) == 0)
       error.SetErrorStringWithFormat("invalid uuid string value '%s'",
                                      value.str().c_str());
     else {