Write screenshots to /tmp/screenshot.png instead of /var/www/screensh…

…ot.png

Fixes #37

/var/www is now owned by root instead of ftc because changing the owner caused the image build to fail because the new symlink /var/www/screenshot.png -> /tmp/screenshot.png does not have a target in the build system, and the only reason why it had to be owned by ftc was writing screenshots.

board/fischertechnik/TXT/device_table.txt

@@ -8,7 +8,6 @@
 # apps still belong to root and thus cannot be touched by ftc
 #
 # <name>                                <type>  <mode>  <uid>   <gid>   <major> <minor> <start> <inc>   <count>
-/var/www                                r       755     1001    1001    -       -       -       -       -
 /opt/ftc/apps                           d       755     1001    1001    -       -       -       -       -
 /rom                                    d       755     0       0       -       -       -       -       -
 /opt/fischertechnik                     r       755     1000    1000    -       -       -       -       -

board/fischertechnik/TXT/rootfs/var/www/screenshot.png

@@ -0,0 +1 @@
+/tmp/screenshot.png

board/fischertechnik/TXT/rootfs/var/www/screenshot.py

@@ -19,9 +19,9 @@
 # for PC based tests use imagemagicks import to grab the X screen. The user
 # ownign the screen needs to give access with "xhost +" beforehand
 if platform.machine() == "armv7l":
-    COMMAND = "fbgrab screenshot.png"
+    COMMAND = "fbgrab /tmp/screenshot.png"
 else:
-    COMMAND = "import -display :0 -window root -geometry 320x240 screenshot.png"
+    COMMAND = "import -display :0 -window root -geometry 320x240 /tmp/screenshot.png"
 
 app = subprocess.Popen(COMMAND.split())
 while app.poll() == None: