Revert "set unique resource before initConnection()"

This reverts commit e8dd2ffd8120c47f9b01a9cb1845b794ce3a25de.
Revert "add a random tag to our default XMPP resource value"

This reverts commit 02f71aa2cf6f73b49588f2f8afdab3ec577ec35c.
guarantee a unique XMPP Resource

Since XMPP Servers can direct traffic based on the XMPP Resource,
ChatSecure should ensure that each install has a unique XMPP Resource.
Otherwise, if someone has two instances of ChatSecure running on the same
account, the XMPP Server might always direct traffic to one but not the
other.  Since ChatSecure does not expose the XMPP Resource to the user, it
should be a random string that is then stored

refs #563 https://github.com/guardianproject/ChatSecureAndroid/pull/563
WIP OtrChatManager.end*Sessions sketch, not used yet
lots of OTR debug statements