Fix a bug in the new version of TMethodCall::ReturnType. The internal variable rettype

cannot be reused as it points to a static variable in TCintFix a bug in the new version of TMethodCall::ReturnType. The internal variable rettype
cannot be reused as it points to a static variable in TCint..
s fixes the nightly builds problems.--This line, and those below, will be ignored--

M    core/meta/src/TMethodCall.cxx


git-svn-id: http://root.cern.ch/svn/root/trunk@24107 27541ba8-7e3a-0410-8455-c3a389f83636