lttng-tools: bump version to 2.9.0

lttng-tools: bump version to 2.9.0

Drop sha256 hash. The combination of md5 and sha1 hashes is enough.

Remove upstream patches:

 - 0001-Fix-snapshot-del-output-with-name-on-musl.patch
   https://github.com/lttng/lttng-tools/commit/07f5023712313d73ab3feac62390a2d50457b7aa

 - 0002-Fix-strerror_r-behavior-is-glibc-specific.patch
   https://github.com/lttng/lttng-tools/commit/b6dacfe27a91af50a1f81a2a7eadf4f34ca75769

 - 0003-Set-thread-stack-size-to-ulimit-soft-value.patch
   https://github.com/lttng/lttng-tools/commit/1a1a34b40ab10a195633b1ed5e2e9b42fdae0a78

Release notes:
  https://lists.lttng.org/pipermail/lttng-dev/2016-November/026763.html

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>