Remove duplicate entries from keybindings and settings tables

The following commit meant to fix LP: #1215440 created duplicated entries in the keybindings and settings tables:
https://github.com/MythTV/packaging/commit/efe0e0c02018b5db6ac77e969372e821f68ffa61

patrick@myhostname:~/workspace$ sudo aptitude install mythtv-database 
The following NEW packages will be installed:
  mythtv-database 
0 packages upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/116 kB of archives. After unpacking 366 kB will be used.
Preconfiguring packages ...              
Selecting previously unselected package mythtv-database.
(Reading database ... 315279 files and directories currently installed.)
Unpacking mythtv-database (from .../mythtv-database_2%3a0.27.0+fixes.20130918.033883b-0ubuntu0mythbuntu3_all.deb) ...
Setting up mythtv-database (2:0.27.0+fixes.20130918.033883b-0ubuntu0mythbuntu3) ...
ERROR 1062 (23000) at line 1148: Duplicate entry 'TV Frontend-CYCLEAUDIOCHAN-myhostname' for key 'PRIMARY'
dpkg: error processing mythtv-database (--configure):
 subprocess installed post-installation script returned error exit status 1
No apport report written because MaxReports is reached already
                                                              Errors were encountered while processing:
 mythtv-database
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install.  Trying to recover:
Setting up mythtv-database (2:0.27.0+fixes.20130918.033883b-0ubuntu0mythbuntu3) ...
ERROR 1062 (23000) at line 1148: Duplicate entry 'TV Frontend-CYCLEAUDIOCHAN-myhostname' for key 'PRIMARY'
dpkg: error processing mythtv-database (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 mythtv-database

This issue affected me and another user: http://ubuntuforums.org/showthread.php?t=2174537&p=12789159

This pull request removes the duplicate entries.

Regards,
Patrick.