[Bug] Fix SONiC installation failure caused by pip/pip3 not found (#1…

…3284)

The main issue is the pip/pip3 command cannot be found when the package is being installed by apt-get.
When using the dpkg install, the searching path is PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
When using the apt-get install, the searching path is PATH=/usr/sbin:/usr/bin:/sbin:/bin
But the pip/pip3 default path is at /usr/local/bin, so dpkg works, but apt-get not work.

How I did it
Export the path /usr/local/bin for pip/pip3.
Make the deb packages can be installed by apt-get.

files/image_config/platform/rc.local

@@ -292,7 +292,7 @@ if [ -f $FIRST_BOOT_FILE ]; then
             mv /etc/apt/sources.list /etc/apt/sources.list.rc-local
             echo "deb [trusted=yes] file:///host/image-$SONIC_VERSION/platform/common /" > /etc/apt/sources.list.d/sonic_debian_extension.list
             LANG=C DEBIAN_FRONTEND=noninteractive apt-get update
-            LANG=C DEBIAN_FRONTEND=noninteractive apt-get -y install /host/image-$SONIC_VERSION/platform/$platform/*.deb
+            LANG=C DEBIAN_FRONTEND=noninteractive apt-get -o DPkg::Path=$PATH:/usr/local/bin -y install /host/image-$SONIC_VERSION/platform/$platform/*.deb
             # Cleanup
             rm -f /etc/apt/sources.list.d/sonic_debian_extension.list
             rm -f /var/lib/apt/lists/_host_image-${SONIC_VERSION}_platform_common_Packages.lz4