Fix:Removal of persons from drawer on All PM

When new message is received, sender is updated
in people table, isActive field is false by default,
so make it true.

Fix: #262

Author: jainkuniya

app/src/main/java/com/zulip/android/models/Person.java

@@ -160,6 +160,7 @@ public static Person getOrUpdate(ZulipApp app, String email, String name,
             // use the person id passed to generate person skeleton object which is consistent
             // with server id.
             person.setId(personId);
+            person.setActive(true);
             app.getDao(Person.class).createOrUpdate(person);
         } else {
             boolean changed = false;
@@ -172,6 +173,7 @@ public static Person getOrUpdate(ZulipApp app, String email, String name,
                 changed = true;
             }
             if (changed) {
+                person.setActive(true);
                 app.getDao(Person.class).update(person);
             }
         }