Description:
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Sending a query parameter such as, "oauth?a[b][c]=d", to the 
OAuthProvider::checkOAuthRequest results in an "Array to 
String" exception.

The cause for this appears to be that OAuth first converts the 
query param into a multi-dimensional array, and then creates 
the signature. (

Instead of trying to convert to an object/array first, I think 
OAuthProvider should treat the params as a 1-D key-value array 
where some of the keys happen to have '[' and ']'.

Reproduce code:
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$consumer->fetch("http://localhost/oauth?a[b][c]=d");
// Note that the below fails on fetch even though it's the "same" as the above (Bug 17572)
// $consumer->fetch("http://localhost/oauth", array('a' => array('b' => array('c' => 'd'))));


$provider = new OAuthProvider();
$provider->is2LeggedEndpoint(true);
$provider->consumerHandler('lookupConsumer');
$provider->timestampNonceHandler('timestampNonceHandler');
$provider->checkOAuthRequest();




Actual result:
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ErrorException [ Notice ]: Array to string conversion