Fixed Analytics request metadata for "os" field
Fixed Analytics request metadata for "os" field

- Previously, all requests had the "os" field set to "ios"
- Now, we check for the os version to device if "os" = "ios" or "watchos"

ibm-bluemix-mobile-services/bms-clientsdk-swift-analytics,ibm-bluemix-mobile-services/bms-clientsdk-swift-analytics,ibm-bluemix-mobile-services/bms-clientsdk-swift-analytics,ibm-bluemix-mobile-services/bms-clientsdk-swift-analytics,ibm-bluemix-mobile-services/bms-clientsdk-swift-analytics