prefer [[ ]] syntax for enable_var checks in sles recipe (#147)

docs/recipes/install/sles12/vanilla/steps.tex

@@ -149,7 +149,7 @@ \subsection{Add \InfiniBand{} support services on {\em master} node} \label{sec:
 
 % begin_ohpc_run
 % ohpc_validation_newline
-% ohpc_command if [ ${enable_ipoib} -eq 1 ];then
+% ohpc_command if [[ ${enable_ipoib} -eq 1 ]];then
 % ohpc_indent 5
 % ohpc_validation_comment Enable ib0
 \begin{lstlisting}[language=bash,literate={-}{-}1,keywords={},upquote=true]
@@ -446,7 +446,7 @@ \subsubsection{Additional Customizations ({\em optional})} \label{sec:addl_custo
 
 % begin_ohpc_run
 % ohpc_validation_newline
-% ohpc_command if [ ${enable_lustre_client} -eq 1 ];then
+% ohpc_command if [[ ${enable_lustre_client} -eq 1 ]];then
 % ohpc_indent 5
 
 % ohpc_validation_comment Install Lustre client on master
@@ -615,7 +615,7 @@ \subsubsection{Import files} \label{sec:file_import}
 
 % begin_ohpc_run
 % ohpc_validation_newline
-% ohpc_command if [ ${enable_ipoib} -eq 1 ];then
+% ohpc_command if [[ ${enable_ipoib} -eq 1 ]];then
 % ohpc_indent 5
 \begin{lstlisting}[language=bash,literate={-}{-}1,keywords={},upquote=true]
 [sms](*\#*) wwsh file import /opt/ohpc/pub/examples/network/sles/ifcfg-ib0.ww
@@ -670,7 +670,7 @@ \subsubsection{Import files} \label{sec:file_import}
 
 % ohpc_validation_newline
 % ohpc_validation_comment Optionally, define IPoIB network settings (required if planning to mount Lustre over IB)
-% ohpc_command if [ ${enable_ipoib} -eq 1 ];then
+% ohpc_command if [[ ${enable_ipoib} -eq 1 ]];then
 % ohpc_indent 5
 \begin{lstlisting}[language=bash,keywords={},upquote=true,basicstyle=\footnotesize\ttfamily]
 # Optionally define IPoIB network settings (required if planning to mount Lustre over IB)
@@ -696,7 +696,7 @@ \subsubsection{Import files} \label{sec:file_import}
 % begin_ohpc_run
 
 % ohpc_validation_comment Optionally, add arguments to bootstrap kernel
-% ohpc_command if [ ${enable_kargs} ]; then
+% ohpc_command if [[ ${enable_kargs} ]]; then
 % ohpc_command    wwsh provision set "${compute_regex}" --kargs=${kargs}
 % ohpc_command fi