Pin PyECLib version for Swift 2.3.0 tests
Pin PyECLib version for Swift 2.3.0 tests

When using Swift 2.3.0, a non-working version of PyECLib tends to be
pulled from PyPI. This patch pins the dependency version to what's
pinned in the OpenStack Kilo release.

scality/ScalitySproxydSwift,scality/ScalitySproxydSwift