[openssh]: move build dep installation to sonic-slave-buster (#8381)

install build dep causes dpkg lock issue in parallel build

Signed-off-by: Guohan Lu <lguohan@gmail.com>

sonic-slave-buster/Dockerfile.j2

@@ -350,6 +350,8 @@ RUN apt-get update && apt-get install -y \
         libsystemd-dev \
         pkg-config
 
+RUN apt-get -y build-dep openssh
+
 # Build fix for ARMHF buster libsairedis
 {%- if CONFIGURED_ARCH == "armhf" %}
        # Install doxygen build dependency packages

src/openssh/Makefile

@@ -19,7 +19,6 @@ $(addprefix $(DEST)/, $(MAIN_TARGET)): $(DEST)/% :
 	stg import -s ../patch/series
 
 	# Build package
-	sudo http_proxy=$(http_proxy) apt-get -y build-dep openssh
 	dpkg-buildpackage -rfakeroot -b -us -uc -j$(SONIC_CONFIG_MAKE_JOBS) --admindir $(SONIC_DPKG_ADMINDIR)
 	popd