Detect all errors in the execute() method.

When the execute() is called without $bindParameters (because the
parameters have been binded previously with the bindParameter() method),
errors were not detected. This patch fixes this.
[auto] Merge from Database

    • #e98d643 — Detect all errors in the execute() method. (Ivan Enderlin, 2013-05-31)

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Merge remote branch 'library-database/master'