labs/buildroot-rootfs: use __SESSION_NAME__ where appropriate

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

labs/buildroot-rootfs/buildroot-rootfs.tex

@@ -58,7 +58,7 @@ \subsection{Init script for USB network setup}
 a ready-to-use shell script that we will add to the {\em init scripts}
 of the Buildroot system. The script is called \code{S30usbgadget} and
 is available from this lab data directory at
-\code{$HOME/buildroot-labs/buildroot-rootfs/}.
+\code{$HOME/__SESSION_NAME__-labs/buildroot-rootfs/}.
 
 We could copy this script directly to our SD card, but this would mean
 that the next time we reflash the SD card with the root filesystem
@@ -270,10 +270,10 @@ \section{Patch the Linux kernel}
 \end{bashinput}
 
 Copy in this directory the two patches that we provided with the data
-of this lab, in \code{$HOME/buildroot-labs/buildroot-rootfs/linux/}:
+of this lab, in \code{$HOME/__SESSION_NAME__-labs/buildroot-rootfs/linux/}:
 
 \begin{bashinput}
-cp $HOME/buildroot-labs/buildroot-rootfs/linux/*.patch \
+cp $HOME/__SESSION_NAME__-labs/buildroot-rootfs/linux/*.patch \
      board/felabs/beagleboneblack/patches/linux/
 \end{bashinput}