pwdgrp.c: Removed unused variable

The 'sc' variable was originally storing the return value of mkdir().
This was causing an issue, so it was changed to make it to where we
ignored the return value with (void). The 'sc' variable was left in
by mistake.

cpukit/libcsupport/src/pwdgrp.c

@@ -63,8 +63,6 @@ static void init_file(const char *name, const char *content)
  */
 static void pwdgrp_init(void)
 {
-  int sc;
-
   /*
    * Do the best to create this directory.
    *