Bumped manifest to 4.310

<?xml version="1.0" encoding="utf-8"?>

<manifest

    xmlns:android="http://schemas.android.com/apk/res/android"

    android:versionCode="17010"

    android:versionName="4.309" package="com.fsck.k9"

    android:versionCode="17011"

    android:versionName="4.310" package="com.fsck.k9"

    >

    <uses-sdk

       android:minSdkVersion="7"