drop iOS 9 checks on ci

Author: maxsokolov

.travis.yml

@@ -13,7 +13,7 @@ env:
 
   matrix:
   - DESTINATION="OS=10.0,name=iPhone 5"          SCHEME="$SCHEME_IOS"     SDK="$IOS_SDK"
-  - DESTINATION="OS=11.0,name=iPhone 6"          SCHEME="$SCHEME_IOS"     SDK="$IOS_SDK"
+  - DESTINATION="OS=11.1,name=iPhone 6"          SCHEME="$SCHEME_IOS"     SDK="$IOS_SDK"
   - DESTINATION="OS=12.0,name=iPhone 7 Plus"     SCHEME="$SCHEME_IOS"     SDK="$IOS_SDK"
 
 script: