A Randomized, Double-Blind, Placebo-Controlled, Active Comparator, One-Week, Cross-Over, Multicenter Study to Evaluate the Efficacy, Patient Preference and Experience of One-Daily, Intranasal Administration of 110mcg Fluticasone Furoate Nasal Spray and 200mcg Fluticasone Propionate Nasal Spray in Adult Subjects with Seasonal Allergic Rhinitis (FFU105927)