OSM Client Installation Fix

Updates stage 3 to present osmclient and IM debian packages.
Updates installer to also install pip requirements.txt if
those files are present from the osmclient .deb package

Fixes bug 1510

Change-Id: I9ee44b265615935fee6c869c6c3c261739370183
Signed-off-by: beierlm <mark.beierl@canonical.com>