environment: fix typo: 'setup_git_directory_gently'

Above the declaration of git_work_tree_cfg, we have: /* This is set by setup_git_dir_gently() and/or git_default_config() */ char *git_work_tree_cfg; It can be verified that there is no function called 'setup_git_dir_gently' by running grep on the codebase: $ grep -R setup_git_dir_gently . ./environment.c:/* This is set by setup_git_dir_gently() and/or git_default_config() */ The comment, introduced in e90fdc39b6 (Clean up work-tree handling), is the only occurrence of the name 'setup_git_dir_gently'. It probably meant 'setup_git_directory_gently' as that is a name of a real function in setup.c. Correct it. Signed-off-by: Abhijeet Sonar <abhijeet.nkt@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>