Bugsplat bug #340345: need to initialize the last two function pointers

in the file I/O method table.

nsprpub/pr/src/pthreads/ptio.c

@@ -2450,6 +2450,8 @@ static PRIOMethods _pr_file_methods = {
     (PRGetpeernameFN)_PR_InvalidStatus,    
     (PRGetsockoptFN)_PR_InvalidStatus,    
     (PRSetsockoptFN)_PR_InvalidStatus,    
+    (PRGetsocketoptionFN)_PR_InvalidStatus,
+    (PRSetsocketoptionFN)_PR_InvalidStatus
 };
 
 static PRIOMethods _pr_tcp_methods = {