[libgtop] Don't try to print a NULL hash_table.

[Robert Roth <robertroth src gnome org>]

commit e0244ad3fc81098cb339acaa98cbe9c1b23a6bf5
Author: Benoit Dejean <bdejean gmail com>
Date:   Sun Jun 21 15:38:32 2015 +0200

    Don't try to print a NULL hash_table.

 examples/pprint.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/examples/pprint.c b/examples/pprint.c
index ae018ea..20a7e9a 100644
--- a/examples/pprint.c
+++ b/examples/pprint.c
@@ -43,9 +43,11 @@ printf("\t%4lu B %3lu " #ARRAY "[%lu] = { ", \
 (unsigned long) sizeof buf->ARRAY, 0,\
 (unsigned long) G_N_ELEMENTS(buf->ARRAY)); \
 for(i = 0; i < SIZE; ++i) { \
-printf ("[ ");\
-PPRINT_HASHTABLE(buf->ARRAY[i].values); \
-printf ("]\n");\
+  if (buf->ARRAY[i].values) {                  \
+    printf ("[ ");                             \
+    PPRINT_HASHTABLE(buf->ARRAY[i].values);    \
+    printf ("]\n");                            \
+  }                                            \
 } \
 printf("} "); \
 } while(0)