fix lint error moving constant to preferences

src/main/java/com/owncloud/android/authentication/PassCodeManager.java

@@ -31,6 +31,7 @@ import android.view.WindowManager;
 import com.owncloud.android.MainApp;
 import com.owncloud.android.ui.activity.FingerprintActivity;
 import com.owncloud.android.ui.activity.PassCodeActivity;
+import com.owncloud.android.ui.activity.Preferences;
 
 import java.util.HashSet;
 import java.util.Set;
@@ -131,6 +132,7 @@ public class PassCodeManager {
 
     private boolean fingerprintIsEnabled() {
         SharedPreferences appPrefs = PreferenceManager.getDefaultSharedPreferences(MainApp.getAppContext());
-        return (appPrefs.getBoolean(FingerprintActivity.PREFERENCE_USE_FINGERPRINT, false));
+        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
+                appPrefs.getBoolean(Preferences.PREFERENCE_USE_FINGERPRINT, false);
     }
 }

src/main/java/com/owncloud/android/ui/activity/FingerprintActivity.java

@@ -77,7 +77,6 @@ public class FingerprintActivity extends AppCompatActivity {
 
     public final static String KEY_CHECK_RESULT = "KEY_CHECK_RESULT";
 
-    public final static String PREFERENCE_USE_FINGERPRINT = "use_fingerprint";
     public static final String ANDROID_KEY_STORE = "AndroidKeyStore";
 
     private KeyStore keyStore;

src/main/java/com/owncloud/android/ui/activity/Preferences.java

@@ -88,6 +88,8 @@ public class Preferences extends PreferenceActivity
 
     private static final String TAG = Preferences.class.getSimpleName();
 
+    public final static String PREFERENCE_USE_FINGERPRINT = "use_fingerprint";
+
     private static final String SCREEN_NAME = "Settings";
 
     private static final int ACTION_SELECT_UPLOAD_PATH = 1;
@@ -267,7 +269,7 @@ public class Preferences extends PreferenceActivity
         }
 
         boolean fPrintEnabled = getResources().getBoolean(R.bool.fingerprint_enabled);
-        fPrint = (SwitchPreference) findPreference(FingerprintActivity.PREFERENCE_USE_FINGERPRINT);
+        fPrint = (SwitchPreference) findPreference(PREFERENCE_USE_FINGERPRINT);
         if (fPrint != null) {
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                 if (FingerprintActivity.isFingerprintCapable(MainApp.getAppContext()) && fPrintEnabled) {