fix identation & trailing space

tests/test_apt.sh

@@ -11,9 +11,9 @@ apt-get clean
 #Testing if sl package exists and remove it
 
 if ( dpkg -s sl >/dev/null 2>&1 ); then
-   echo "Removing already installed testing package"
-   apt-get remove -y sl
-fi 
+    echo "Removing already installed testing package"
+    apt-get remove -y sl
+fi
 
 # Installation testing package sl
 apt-get update