sanitise sign comparisons

This is a mechanical change addressing the various sign comparison warnings that
are identified by both clang and gcc.  This helps cleanup some of the warning
spew that occurs during builds.

llvm-svn: 205390
diff --git a/lldb/source/Commands/CommandObjectQuit.cpp b/lldb/source/Commands/CommandObjectQuit.cpp
index ffe2a92..dd0efc6 100644
--- a/lldb/source/Commands/CommandObjectQuit.cpp
+++ b/lldb/source/Commands/CommandObjectQuit.cpp
@@ -53,7 +53,7 @@
             continue;
         const TargetList& target_list(debugger_sp->GetTargetList());
         for (uint32_t target_idx = 0;
-             target_idx < target_list.GetNumTargets();
+             target_idx < static_cast<uint32_t>(target_list.GetNumTargets());
              target_idx++)
         {
             TargetSP target_sp(target_list.GetTargetAtIndex(target_idx));