Making TCP_KEEPIDLE socket option optional
Making TCP_KEEPIDLE socket option optional

Not all implementations of the python socket library support
TCP_KEEPIDLE, so only try to set it when supported. Fixes bug 879195.

Change-Id: I2f062a346a60c69f52d23f70332d7c9da4ecdf35

tanglei528/glance,vuntz/glance,JioCloud/glance,openstack/glance,rajalokan/glance,redhat-openstack/glance,SUSE-Cloud/glance,JioCloud/glance,SUSE-Cloud/glance,akash1808/glance,openstack/glance,dims/glance,wkoathp/glance,ozamiatin/glance,takeshineshiro/glance,ntt-sic/glance,vuntz/glance,darren-wang/gl,akash1808/glance,rickerc/glance_audit,jumpstarter-io/glance,sigmavirus24/glance,kfwang/Glance-OVA-OVF,jumpstarter-io/glance,kfwang/Glance-OVA-OVF,citrix-openstack-build/glance,tanglei528/glance,cloudbau/glance,ozamiatin/glance,saeki-masaki/glance,saeki-masaki/glance,cloudbau/glance,paramite/glance,ntt-sic/glance,scripnichenko/glance,dims/glance,redhat-openstack/glance,wkoathp/glance,scripnichenko/glance,takeshineshiro/glance,stevelle/glance,klmitch/glance,rajalokan/glance,paramite/glance,rickerc/glance_audit,openstack/glance,klmitch/glance,sigmavirus24/glance,darren-wang/gl,citrix-openstack-build/glance,stevelle/glance