elements/base/sndfile.bst: fix dependency

We mistakenly added 'buildsystem-autotools' as a runtime dependency in
!573
which resulted in exporting several typical Sdk elements like
'autoconf' or 'automake' into Plarform.
7 jobs for EmersonBernier/sndfile_fix_dep in 100 minutes and 24 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Flatpak
failed #176199986
aarch64
app_aarch64

00:56:36

canceled #176199988
armhf
app_arm

01:40:23

canceled #176199984
x86_64 cache_i686
app_i686

01:40:23

canceled #176199979
x86_64 cache_x86_64
app_x86_64

01:40:23

 
  Vm
canceled #176199996
cache_x86_64 x86_64
desktop_vm_image_x86_64

canceled #176199993
x86_64 cache_x86_64
minimal_systemd_vm_image_x86_64

canceled #176199990
x86_64 cache_x86_64
minimal_vm_image_x86_64

 
Name Stage Failure
failed
app_aarch64 Flatpak
  Build Queue: processed 12,  skipped 292, failed 0 
Push Queue: processed 203, skipped 93, failed 1


make: *** [Makefile:25: build] Error 255
Uploading artifacts...
/builds/freedesktop-sdk/freedesktop-sdk/cache/buildstream/logs: found 1300 matching files
Uploading artifacts to coordinator... ok
id=176199986 responseStatus=201 Created token=hHhe5bdC
ERROR: Job failed: exit code 1