Binaries are identical before and after this change.

The manpage for dh_bash-completion is currently not re-generated during
builds, because it is not listed as a dependency of any debian/rules
target.  Packaging only works because the output file is present in the
repository.

This patch removes the output file from the repository and adds it as a
dependency of the dh_install target, so that the manpage gets
re-generated during builds.

This patch also replaces the manual parsing of the upstream version with
the DEB_VERSION_UPSTREAM from /usr/share/dpkg/pkg-info.mk.  Thanks to
Juhani Numminen for suggesting this change [1].

[1] https://bugs.debian.org/877450#81

Since debhelper 10, autoreconf is enabled by default.  Thanks to Juhani
Numminen for suggesting this change.

[1] https://bugs.debian.org/877450#81

During the adoption of bash-completion, the changes from NMUs were
missed.  This patch incorporates the third of them (version 2.1-4.3).

This change was suggested by Andreas Henriksson [1].  The bug report [2]
associated with this NMU is bug 820247.

[1] https://bugs.debian.org/877450#12
[2] https://bugs.debian.org/820247

During the adoption of bash-completion, the changes from NMUs were
missed.  This patch incorporates the first of them (version 2.1-4.1).

This change was suggested by Andreas Henriksson [1].  The diff was
retrieved from the bug report which resulted in the NMU [2].

[1] https://bugs.debian.org/877450#12
[2] https://bugs.debian.org/755986#20

make install used to check for installed files under
/etc/bash_completion.d, but this is no longer necessary, since that
directory is deprecated (nothing else is installed in it).

Package bts provides its own completion file, which conflicts with the
completion file provided by bash-completion.  This patch drops the
version provided by bash-completion.

Package adb provides its own completion file, which conflicts with the
completion file provided by bash-completion.  This patch drops the
version provided by bash-completion.