Get version from installed package if available

Change-Id: I28ba441351a62f249c5af190ffb9efdd109ccef2
Signed-off-by: tierno <alfonso.tiernosepulveda@telefonica.com>
diff --git a/osm_common/__init__.py b/osm_common/__init__.py
index 6fc66a5..8bdb9f5 100644
--- a/osm_common/__init__.py
+++ b/osm_common/__init__.py
@@ -15,5 +15,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-version = '6.0.2.post3'
-date_version = '2019-09-19'
+version = '7.0.0.post2'
+date_version = '2019-12-20'
+
+# try to get version from installed package. Skip if fails
+try:
+    from pkg_resources import get_distribution
+    version = get_distribution("osm_common").version
+except Exception:
+    pass