PCBC-219 fix bug

Environment 

```
aleksandr@home:~/Work/OpenSource$ uname -a
Linux home 3.5.0-47-generic #71-Ubuntu SMP Wed Feb 19 00:00:07 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
aleksandr@home:~/Work/OpenSource$ php -v
PHP 5.4.6-1ubuntu1.7 (cli) (built: Feb 28 2014 23:17:47) 
Copyright (c) 1997-2012 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2012 Zend Technologies
    with Xdebug v2.2.1, Copyright (c) 2002-2012, by Derick Rethans
aleksandr@home:~/Work/OpenSource$ php -i
...
couchbase

couchbase support => enabled
version => 1.2.0
libcouchbase version => 2.2.0
json support => yes
fastlz support => yes
zlib support => yes
igbinary support => no

Directive => Local Value => Master Value
couchbase.compression_factor => 1.3 => 1.3
couchbase.compression_threshold => 2000 => 2000
couchbase.compressor => none => none
couchbase.config_cache => no value => no value
couchbase.durability_default_poll_interval => 100000 => 100000
couchbase.durability_default_timeout => 40000000 => 40000000
couchbase.instance.persistent => On => On
couchbase.restflush => On => On
couchbase.serializer => php => php
couchbase.skip_config_errors_on_connect => Off => Off
couchbase.view_timeout => 75 => 75
...
```

Script for test

```
<?php 

$cb = new \Couchbase(...);

$data = array(
	floatval(763.123456), 
	floatval(1700.00),
	floatval('700.00'),
	8283.19956, 
);

foreach ($data as $key => $value) {
	$cb->set('ind.' . $key, $value);
}
var_dump($data);

$fromCb = array();
foreach ($data as $key => $value) {
	$fromCb[] = $cb->get('ind.' . $key);
}
var_dump($fromCb);
```

Run result

```
aleksandr@home:~/Work/OpenSource$ php cb.php
array(4) {
  [0] =>
  double(763.123456)
  [1] =>
  double(1700)
  [2] =>
  double(700)
  [3] =>
  double(8283.19956)
}
array(4) {
  [0] =>
  double(763.123456)
  [1] =>
  double(1700123456)
  [2] =>
  double(7000123456)
  [3] =>
  double(8283.19956)
}
```