Fix up lldb build for llvm r217172.

Changes reference to 4th element in version_min_command from reserved to sdk.

llvm-svn: 217185
diff --git a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
index 8d7fe04..67be5a5 100644
--- a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
+++ b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
@@ -5026,9 +5026,9 @@
             {
                 if (m_data.GetU32 (&offset, &lc.version, (sizeof(lc) / sizeof(uint32_t)) - 2))
                 {
-                    const uint32_t xxxx = lc.reserved >> 16;
-                    const uint32_t yy = (lc.reserved >> 8) & 0xffu;
-                    const uint32_t zz = lc.reserved  & 0xffu;
+                    const uint32_t xxxx = lc.sdk >> 16;
+                    const uint32_t yy = (lc.sdk >> 8) & 0xffu;
+                    const uint32_t zz = lc.sdk & 0xffu;
                     if (xxxx)
                     {
                         m_sdk_versions.push_back(xxxx);