[gnote] Fix crash when DESKTOP_SESSION environment variable is not set

[Aurimas Černius <aurimasc src gnome org>]

commit 4152b10749cd6389e6523bc66b770dcb1c7a4d98
Author: Aurimas Černius <aurisc4 gmail com>
Date:   Mon Jul 6 21:13:13 2015 +0300

    Fix crash when DESKTOP_SESSION environment variable is not set
    
    Fixes Bug 752024.

 src/mainwindow.cpp |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/src/mainwindow.cpp b/src/mainwindow.cpp
index d7808db..32b5298 100644
--- a/src/mainwindow.cpp
+++ b/src/mainwindow.cpp
@@ -117,9 +117,11 @@ bool MainWindow::use_client_side_decorations()
       std::vector<std::string> desktops;
       sharp::string_split(desktops, setting, ",");
       const char *current_desktop = std::getenv("DESKTOP_SESSION");
-      FOREACH(std::string de, desktops) {
-        if(de == current_desktop) {
-          s_use_client_side_decorations = 1;
+      if (current_desktop) {
+        FOREACH(std::string de, desktops) {
+         if(de == current_desktop) {
+           s_use_client_side_decorations = 1;
+         }
         }
       }
     }