Remove bullseye-backports from build, remove buster-backports from docs

debian/vitastor.Dockerfile

@@ -16,23 +16,15 @@ RUN set -e -x; \
         wget https://vitastor.io/debian/pubkey.gpg -O /etc/apt/trusted.gpg.d/vitastor.gpg; \
         echo "deb https://vitastor.io/debian $REL main" >> /etc/apt/sources.list; \
     fi; \
-    if [ "$REL" = "bullseye" ]; then \
-        echo "deb http://deb.debian.org/debian $REL-backports main" >> /etc/apt/sources.list; \
-        echo >> /etc/apt/preferences; \
-        echo 'Package: *' >> /etc/apt/preferences; \
-        echo "Pin: release a=$REL-backports" >> /etc/apt/preferences; \
-        echo 'Pin-Priority: 500' >> /etc/apt/preferences; \
-    fi; \
     grep '^deb ' /etc/apt/sources.list | perl -pe 's/^deb/deb-src/' >> /etc/apt/sources.list; \
     perl -i -pe 's/Types: deb$/Types: deb deb-src/' /etc/apt/sources.list.d/debian.sources || true; \
     echo 'APT::Install-Recommends false;' >> /etc/apt/apt.conf; \
     echo 'APT::Install-Suggests false;' >> /etc/apt/apt.conf
 
 RUN apt-get update
-RUN apt-get -y install fio liburing-dev libgoogle-perftools-dev devscripts
+RUN apt-get -y install fio liburing-dev libgoogle-perftools-dev devscripts libjerasure-dev cmake libibverbs-dev libisal-dev libnl-3-dev libnl-genl-3-dev curl
 RUN apt-get -y build-dep fio
 RUN apt-get --download-only source fio
-RUN apt-get update && apt-get -y install libjerasure-dev cmake libibverbs-dev libisal-dev libnl-3-dev libnl-genl-3-dev curl
 
 ADD . /root/vitastor
 RUN set -e -x; \

docs/installation/packages.en.md

@@ -16,8 +16,6 @@
   - Debian 10 (Buster): `deb https://vitastor.io/debian buster main`
   - Add `-oldstable` to bookworm/bullseye/buster in this line to install the last
     stable version from 0.9.x branch instead of 1.x
-- For Debian 10 (Buster) also enable backports repository:
-  `deb http://deb.debian.org/debian buster-backports main`
 - Install packages: `apt update; apt install vitastor lp-solve etcd linux-image-amd64 qemu-system-x86`
 
 ## CentOS

docs/installation/packages.ru.md

@@ -16,8 +16,6 @@
   - Debian 10 (Buster): `deb https://vitastor.io/debian buster main`
   - Добавьте `-oldstable` к слову bookworm/bullseye/buster в этой строке, чтобы
     установить последнюю стабильную версию из ветки 0.9.x вместо 1.x
-- Для Debian 10 (Buster) также включите репозиторий backports:
-  `deb http://deb.debian.org/debian buster-backports main`
 - Установите пакеты: `apt update; apt install vitastor lp-solve etcd linux-image-amd64 qemu-system-x86`
 
 ## CentOS