setPattern should accept string values

[CrazyMuffin]

When I attempt to extend class and set my own pattern, application crashes because:

1. When trying to set string, setPattern declines the value because of invalid typehint.
2. When I set the string value into array, application crashes further down as values in Finder::names should be string only. (they are later passed into preg_match function).

Invalid typehint:

JMSTranslationBundle/Translation/Extractor/FileExtractor.php

Lines 173 to 176 in c837dc6

	public function setPattern(array $pattern)
	{
	$this->pattern = $pattern;
	}

Function call that expects string:

JMSTranslationBundle/Translation/Extractor/FileExtractor.php

Lines 201 to 203 in c837dc6

	if ($this->pattern) {
	$finder->name($this->pattern);
	}

Function itself:
https://github.com/symfony/symfony/blob/9e82562948253bf547243aa1c4cf6ec734d608da/src/Symfony/Component/Finder/Finder.php#L150-L170

Solution:

1. Change argument typehint to string
2. Allow array, but iterate values on $finder::name call

Workaround:
Copy class but reimplement everything