Given the information we current have--and obviously that will change as more details emerge--it should not be called a coup attempt. Let's go to the Oxford Companion to Politics of the World, under coup d'état. First sentence:
A nonconstitutional change of government leadership carried out with the use or threatened use of violence is known as a coup d'état.
An attempted coup, then, is an effort to change the leadership, in this case the president. It is not entirely clear what the police thought they were going to accomplish, but ousting Correa was not obviously part of it. Perhaps they hoped the armed forces would join in and overthrow him--if that turns out to be the case, I might change my mind. I've seen reference to the air force, but it's not yet clear what their goal was, whether they were coordinated at all, etc. If they just hoped to intimidate him, then it isn't good but it isn't a coup attempt. Fortunately, the following was the case:
The head of the armed forces, Ernesto Gonzalez, said troops remained loyal to Correa. "We are in a state of law. We are loyal to the maximum authority, which is the president."
And let's hope it stays that way.
Update: FWIW, the government of Ecuador does not necessarily refer to a coup attempt, but rather to an "insubordination." Correa himself, though, of course does.