update enable_ping_and_ssh example to include quantum security groups

Fixes bug 1158527

Change-Id: Ic7d74ea90ab85a9531821e9e20a990e9a50da375
Fix image locations

It seems, that the figures have not been moved to the new location
during the extraction of the cinder manual. This fix corrects this error
for the XenAPINFS driver's section.

Change-Id: I2fad4d7ca79f67889f05832490473d14d1b452f9
Merge "Fix image locations"
Merge "update enable_ping_and_ssh example to include quantum security groups"