BGP quagga not deleting old routes

To answer your question directly, this is expected behavior by OSPF and not a bug in Quagga.

So first, let's take a look at the DR/BDR section of the RFC.

Designated Router
    The Designated Router selected for the attached network.  The
    Designated Router is selected on all broadcast and NBMA networks
    by the Hello Protocol.  Two pieces of identification are kept
    for the Designated Router: its Router ID and its IP interface
    address on the network.  The Designated Router advertises link
    state for the network; this network-LSA is labelled with the
    Designated Router's IP address.  The Designated Router is
    initialized to 0.0.0.0, which indicates the lack of a Designated
    Router.

Backup Designated Router
    The Backup Designated Router is also selected on all broadcast
    and NBMA networks by the Hello Protocol.  All routers on the
    attached network become adjacent to both the Designated Router
    and the Backup Designated Router.  The Backup Designated Router
    becomes Designated Router when the current Designated Router
    fails.  The Backup Designated Router is initialized to 0.0.0.0,
    indicating the lack of a Backup Designated Router.

If the BDR field in the Hello packet header is set to 0.0.0.0, it means you do not have a BDR elected.

In your case this is because you have your other router set to a priority of 0, this makes the router ineligible to become a BDR (this is why you see "DROther" and not "BDR"). You just need to set the priority on your other router to something that isn't 0.

Here is the other piece from the RFC for some more context.

Router Priority
    An 8-bit unsigned integer.  When two routers attached to a
    network both attempt to become Designated Router, the one with
    the highest Router Priority takes precedence.  A router whose
    Router Priority is set to 0 is ineligible to become Designated
    Router on the attached network.  Advertised in Hello packets
    sent out this interface.

https://www.ietf.org/rfc/rfc2328.txt

By the data that you give us, this one is an interesting part. Unless you had change the neighbors for your safety, and put the conf here, i think you need to explaind why your iBGP neighbor has the same IP address of your UPDATE SOURCE? This one is like if your iBGP share your same host.

neighbor 1.1.1.1 description "R101 BGP interconnect"
neighbor 1.1.1.1 update-source 1.1.1.1
neighbor 1.1.1.1 next-hop-self
neighbor 1.1.1.1 send-community both
neighbor 1.1.1.1 soft-reconfiguration inbound

neighbor 1.1.1.2 description "R102 BGP interconnect"
neighbor 1.1.1.2 update-source 1.1.1.2
neighbor 1.1.1.2 next-hop-self
neighbor 1.1.1.2 send-community both
neighbor 1.1.1.2 soft-reconfiguration inbound