Fix Eclipse not finding bcprov.jar

Commit 08da52a45633704c1486a6a92d536713c80e4bce changed
the Ant builder to consume "lib/bcprov-jdk15on-151.jar"
instead of "lib/bcprov.jar". Unfortunately, it did not update the
Eclipse project configuration to reflect that change.

This commit fixes that.
(Also, we might go for using bcprov from the distribution instead of lib/ as well.. It *is* in package management from Ubuntu, albeit outdated.)