Grub2 was hanging due to a infinite loop on incorrect entries.

Entries that contained the string ".conf" but did not end with it
were causing the loop to never exit. Move dotconf pointer up
if it doesn't trigger the loop exit condition so that
grub_strstr can return a NULL pointer at some point.

Index: grub-2.12/grub-core/commands/blscfg.c
===================================================================
--- grub-2.12.orig/grub-core/commands/blscfg.c
+++ grub-2.12/grub-core/commands/blscfg.c
@@ -850,7 +850,7 @@ static void create_entry (struct bls_ent
   do
     {
       dotconf = grub_strstr(dotconf, ".conf");
-    } while (dotconf != NULL && dotconf[5] != '\0');
+    } while (dotconf != NULL && dotconf[5] != '\0' && *(++dotconf));
   if (dotconf)
     dotconf[0] = '\0';