src-release.sh: Convert src-release to a shell script

src-release.sh: Convert src-release to a shell script

This began as an attempt to make a few small changes to src-release
but heeding the comments at the top of the file it seemed it might be
wise to convert it to a shell script instead which should hopefully
be more maintainable.

This shell script contains most of the functionality of the Makefile
version. It can be run like this:

  # This will build gdb and compress with bzip2, gzip and xz
  ./src-release.sh -bgx gdb

The functionality that has been removed is building tarballs for insight
and gnats, which were broken in the current repository layout and
gas+binutils which amounted to basically the same thing as binutils so
didn't seem worth keeping. The script always builds a tar file,
compression is optional, so no need for specific commands to build tar
files rather than compressed tar files.

The build of gas releases has been fixed, as has extraction of version
numbers which had been broken since the switch to configure.ac files
and AC_INIT.

I also removed the code for distcleaning the intl sub-directory as it
seems like that issue has been fixed.

The script is capable of compressing with bzip2, gzip and xz which
should cover all formats available on gnu.org.

I tested it by producing release tarballs which are substantially
identical to the ones produced by the src-release script.

ChangeLog:

2014-08-27  Will Newton  <will.newton@linaro.org>

	* src-release.sh: New file.
	* src-release: Remove file.