Changes in dof_map.C for -Wshadow.

Issue #24.
Changes in dof_map_constraints.C for -Wshadow.

Issue #24.
Changes in uniform_refinement_estimator.C for -Wshadow.

Issue #24.
Changes in weighted_patch_recovery_estimator.C for -Wshadow.

Issue #24.
Changes in boundary_info.C for -Wshadow.

Issue #24.
Changes in legacy_xdr_io.C for -Wshadow.

Issue #24.
Changes in mesh_base.C for -Wshadow.

Issue #24.
Changes in mesh_communication_global_indices.C for -Wshadow.

Issue #24.
Changes in xdr_io.C for -Wshadow.

Issue #24.
Changes in patch_recovery_error_estimator.C for -Wshadow.

Issue #24.