Redo leak fix in camera metadata handling.
Redo leak fix in camera metadata handling.

See also: r12758, the previous attempt which did not build with GCC or
Clang.

git-svn-id: 03a8048b5ee8463be5048a3801110fb50f378627@12760 d0ab736e-dc22-4aeb-8dc9-08def0aa14fd

kmdouglass/Micro-Manager,kmdouglass/Micro-Manager