rhbz: replace obsolete methods by their substitutes

- due to changes described here http://post-office.corp.redhat.com/archives/bugzilla-development-list/2012-December/msg00004.html
- replaced RPC method names:
  - bugzilla.getBug        -> Bug.get
  - bugzilla.addAttachment -> Bug.add_attachment
- works with:
  - https://bugzilla.redhat.com/ [version 4.2.4-7]
  - https://partner-bugzilla.redhat.com/ [version 4.2.4-7]
  - https://bzweb01-devel.app.eng.rdu.redhat.com/ [version 4.4.rc1.b02]
- closes trac#921

Related to rhbz#991088

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Jiri Moskovcak <jmoskovc@redhat.com>

Conflicts:
	src/plugins/rhbz.c
	src/plugins/rhbz.h
reporter-bugzilla: use base64 XMLRPC type for encoded data instead of string type

- obsolete: 'bugzilla.addAttachment' accepted base64 data in string variable
  and stored them in database decoded

- current: 'Bug.add_attachment' accepts base64 data but it must be stored in
  base64 type, otherwise server doesn't decode the data and stores them as they
  are

- related to issue #117

Related to rhbz#991088

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Jiri Moskovcak <jmoskovc@redhat.com>
rhbz: get id of duplicate from correct field

This problem was found in dump directories uploaded by Emergency
analysis

Related to rhbz#991088

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Martin Milata <mmilata@redhat.com>
Signed-off-by: Jiri Moskovcak <jmoskovc@redhat.com>