[CB-4386] changed ios platform guide to add ios (used to be add android)

[CB-4386] changed ios platform guide to add ios (used to be add android)

At [0], ("Open a Project in the SDK" section):

$ cordova platform add android

Should be:

$ cordova platform add ios

[0] http://docs.phonegap.com/en/3.0.0/guide_platforms_ios_index.md.html#iOS%20Platform%20Guide_open_a_project_in_the_sdk