`ClasUtilsFile.getFileList(String,String,String)` passes null for non-null parameter of `getFileList(String)`

[c-dilks]

rank 7 spotbugs bug

[INFO] --- spotbugs:4.9.6.0:check (default-cli) @ clas-utils ---
[INFO] BugInstance size is 1
[INFO] Error size is 0
[INFO] Total bugs: 1
[ERROR] High: Non-virtual method call in org.jlab.utils.system.ClasUtilsFile.getFileList(String, String, String) passes null for non-null parameter of getFileList(String) [org.jlab.utils.system.ClasUtilsFile] At ClasUtilsFile.java:[line 146] NP_NULL_PARAM_DEREF_NONVIRTUAL

[c-dilks]

this getFileList overload is unused, should we just remove it?