fix(sw dev1): fragile listings

workshops/software_development/sections/filesystem.tex

@@ -58,7 +58,7 @@
 
 \subsection{Environment}
 \label{sec:fs:env}
-\begin{frame}{\insertsectionhead}
+\begin{frame}[fragile]{\insertsectionhead}
 	\framesubtitle{\insertsubsectionhead}
 	
 	\begin{columns}[onlytextwidth]
@@ -85,7 +85,7 @@ export PATH=/usr/bin:/usr/local/bin
 
 \subsection{Software execution}
 \label{sec:fs:exec}
-\begin{frame}{\insertsectionhead}
+\begin{frame}[fragile]{\insertsectionhead}
 	\framesubtitle{\insertsubsectionhead}
 	\begin{itemize}
 		\item Basics
@@ -104,7 +104,7 @@ export PATH=/usr/bin:/usr/local/bin
 
 \subsection{Example}
 \label{sec:fs:ex}
-\begin{frame}{\insertsectionhead}
+\begin{frame}[fragile]{\insertsectionhead}
 	\framesubtitle{\insertsubsectionhead}
 	\begin{columns}[onlytextwidth]
 		\column{0.55\textwidth}