unistd::getgrouplist: respond to comments

Author: JayH5

src/unistd.rs

@@ -1051,12 +1051,12 @@ pub fn getgrouplist(user: &CString, group: Gid) -> Result<Vec<Gid>> {
         if ret >= 0 {
             unsafe { groups.set_len(ngroups as usize) };
             return Ok(groups);
-        }
+        } else if ret == -1 {
+            // Returns -1 if ngroups is too small, but does not set errno.
+            // BSD systems will still fill the groups buffer with as many
+            // groups as possible, but Linux manpages do not mention this
+            // behavior.
 
-        // Returns -1 if ngroups is too small, but does not set errno.
-        // BSD systems will still fill the groups buffer with as many groups
-        // as possible, but Linux manpages do not mention this behavior.
-        if ret == -1 {
             let cap = groups.capacity();
             if cap >= ngroups_max as usize {
                 // We already have the largest capacity we can, give up