Update OptionGroup::SetValue to take StringRef.

Then deal with all the fallout.

Differential Revision: https://reviews.llvm.org/D24847

llvm-svn: 282265
diff --git a/lldb/source/Interpreter/OptionValueChar.cpp b/lldb/source/Interpreter/OptionValueChar.cpp
index bfc39ae..6423185 100644
--- a/lldb/source/Interpreter/OptionValueChar.cpp
+++ b/lldb/source/Interpreter/OptionValueChar.cpp
@@ -57,7 +57,7 @@
   } break;
 
   default:
-    error = OptionValue::SetValueFromString(value.str().c_str(), op);
+    error = OptionValue::SetValueFromString(value, op);
     break;
   }
   return error;