fix new String:realloc* variants always to zero-terminate the string

sql/sql_string.cc

@@ -81,7 +81,7 @@ bool String::real_alloc(uint32 length)
 
    @retval true An error occured when attempting to allocate memory.
 */
-bool String::realloc(uint32 alloc_length)
+bool String::realloc_raw(uint32 alloc_length)
 {
   if (Alloced_length <= alloc_length)
   {
@@ -109,7 +109,6 @@ bool String::realloc(uint32 alloc_length)
     Ptr= new_ptr;
     Alloced_length= len;
   }
-  Ptr[alloc_length]=0;			// This make other funcs shorter
   return FALSE;
 }
 

sql/sql_string.h

@@ -255,17 +255,30 @@ public:
     return real_alloc(arg_length);
   }
   bool real_alloc(uint32 arg_length);			// Empties old string
-  bool realloc(uint32 arg_length);
+  bool realloc_raw(uint32 arg_length);
+  bool realloc(uint32 arg_length)
+  {
+    if (realloc_raw(arg_length))
+      return TRUE;
+    Ptr[arg_length]=0;        // This make other funcs shorter
+    return FALSE;
+  }
   bool realloc_with_extra(uint32 arg_length)
   {
     if (extra_alloc < 4096)
       extra_alloc= extra_alloc*2+128;
-    return realloc(arg_length + extra_alloc);
+    if (realloc_raw(arg_length + extra_alloc))
+      return TRUE;
+    Ptr[arg_length]=0;        // This make other funcs shorter
+    return FALSE;
   }
   bool realloc_with_extra_if_needed(uint32 arg_length)
   {
     if (arg_length < Alloced_length)
+    {
+      Ptr[arg_length]=0; // behave as if realloc was called.
       return 0;
+    }
     return realloc_with_extra(arg_length);
   }
   inline void shrink(uint32 arg_length)		// Shrink buffer