Close a memory leak in configuration code
Close a memory leak in configuration code

This was causing configuration failures on address sanitizer builds.

efcs/benchmark,ntx-/benchmark,fuchsia-mirror/third_party-benchmark,codygray/benchmark,nickhutchinson/benchmark-cxx03,everbase/benchmark,codygray/benchmark,nickhutchinson/benchmark-cxx03,mockingbirdnest/benchmark,nickhutchinson/benchmark-cxx03,mockingbirdnest/benchmark,nickhutchinson/benchmark,efcs/benchmark,nickhutchinson/benchmark-cxx03,codygray/benchmark,codygray/benchmark,mockingbirdnest/benchmark,mockingbirdnest/benchmark,nickhutchinson/benchmark,fuchsia-mirror/third_party-benchmark,google/benchmark,everbase/benchmark,fuchsia-mirror/third_party-benchmark,google/benchmark,ntx-/benchmark,everbase/benchmark,ntx-/benchmark,disconnect3d/benchmark,nickhutchinson/benchmark,efcs/benchmark,google/benchmark,nickhutchinson/benchmark,efcs/benchmark,disconnect3d/benchmark,ntx-/benchmark,disconnect3d/benchmark,fuchsia-mirror/third_party-benchmark,disconnect3d/benchmark,everbase/benchmark