[FIX] fix for issue #449 (#462)

Author: pwighton

neurodocker/templates/freesurfer.yaml

@@ -56,7 +56,7 @@ binaries:
     # From https://github.com/freesurfer/freesurfer/blob/54018f7d6f620d6288b28f50e14a0a4ba421757c/Dockerfile#L20-L42
     # freesurfer env
     OS: "Linux"
-    PATH: "{{ self.install_path }}/bin:{{ self.install_path }}/fsfast/bin:{{ self.install_path }}/tktools:{{ self.install_path }}/mni/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+    PATH: "{{ self.install_path }}/bin:{{ self.install_path }}/fsfast/bin:{{ self.install_path }}/tktools:{{ self.install_path }}/mni/bin:$PATH"
     FREESURFER_HOME: "{{ self.install_path }}"
     FREESURFER: "{{ self.install_path }}"
     SUBJECTS_DIR: "{{ self.install_path }}/subjects"