sysstat: upgrade 12.7.7 -> 12.7.8

sysstat: upgrade 12.7.7 -> 12.7.8

Changelog:
* sar/sadf: Add new metric kbshmem.
* sar/sadf: Now compute used memory as total memory - available memory.
* sadf: Set availablekb to frmkb during conversion.
* cifsiostat, iostat, mpstat, tapestat: Add new option -U to display
  timestamps in seconds since the Epoch.
* Trap SIGTERM with all sysstat commands.
* mpstat: Go to next line when Ctrl/C is pressed.
* Add support for out-of-tree building and testing.
* sar: A_PWR_BAT: Fix wrong size used in memory initialization.
* Makefile.in: Update dependencies for install_man target.
* Makefile.in: Remove unused TFLAGS variable.
* Makefile.in: Remove old references to nfsiostat.
* DTD and XSD documents updated.
* NLS translations updated.
* sar, mpstat, iostat, cifsiostat and tapestat manual pages updated.
* Various cosmetic changes in code and Makefile.
* do_test: Add test target for out-of-tree build.
* systest: Explicitly set signal to SIGINT.
* Non regression tests: Remove root symlink in tests directory.
* Non regression tests updated.

Signed-off-by: Gyorgy Sarvari <skandigraun@gmail.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>