Not possible to create empty cmake-config with sdktool

When creating an "empty" cmake-config through sdktool, it will still write a single empty value into the valuelist (excerpt from profiles.xml below). QtCreator later complains when running cmake (right click on project -> Run CMake) that the configuration was changed on disk (see screenshot)

The call to sdktool looks as follows:

sdktool addKit --id kit_gcc49_cmake \
--name "Gcc 4.9 cmake" \
--debugger gdb_7_11 \
--debuggerengine 1 \
--Ctoolchain ProjectExplorer.ToolChain.Gcc:tc_gcc49 \
--Cxxtoolchain ProjectExplorer.ToolChain.Gcc:tc_gccpp49 \
--cmake cmake \
--devicetype Desktop \
--cmake-config ""

The problematic entry is the empty value inside valuelist. If I remove it manually, the complain from QtCreator goes away.

<qtcreator>
 <data>
  <variable>Profile.0</variable>
  <valuemap type="QVariantMap">
   <value type="bool" key="PE.Profile.AutoDetected">true</value>
   <valuemap type="QVariantMap" key="PE.Profile.Data">
    <valuelist type="QVariantList" key="CMake.ConfigurationKitInformation">
     <value type="QString"></value>
    </valuelist>

..

Not passing --cmake-config is not an option because QtCreator will then fill in some defaults that we really do not want.