Fix two warnings in diffdir.c : edp1/edp2 may be used uninitialized

[Gabriel Linder]

Index: diffdir.c
===================================================================
RCS file: /cvs/src/usr.bin/diff/diffdir.c,v
retrieving revision 1.40
diff -u -r1.40 diffdir.c
--- diffdir.c    14 Nov 2010 18:24:43 -0000    1.40
+++ diffdir.c    18 Nov 2011 10:57:54 -0000
@@ -48,8 +48,8 @@
 void
 diffdir(char *p1, char *p2, int flags)
 {
-    struct dirent *dent1, **dp1, **edp1, **dirp1 = NULL;
-    struct dirent *dent2, **dp2, **edp2, **dirp2 = NULL;
+    struct dirent *dent1, **dp1, **edp1 = NULL, **dirp1 = NULL;
+    struct dirent *dent2, **dp2, **edp2 = NULL, **dirp2 = NULL;
     size_t dirlen1, dirlen2;
     char path1[MAXPATHLEN], path2[MAXPATHLEN];
     int pos;