qtwebkit: remove false dependency on leveldb
qtwebkit: remove false dependency on leveldb

The qtwebkit configure test never succeeds in finding system leveldb
(ie qtwebkit internal copy of leveldb is always used) so leveldb is a
false dependency.

This change allows qtwebkit to be built in a disto which enables
security_flags.inc (it's otherwise blocked since the leveldb recipe
fails to build when security_flags.inc is used).

Signed-off-by: Andre McCurdy <8f09cea6116be1c651ee99f9f5914cb35309ce01@gmail.com>
Signed-off-by: Martin Jansa <516df3ff67e1fa5d153800b15fb204c0a1a389dc@gmail.com>

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