Enable Fedora 19 on DevStack

Fedora uses a special PROMPT_COMMAND for screen terminal types,
which are the default with DevStack.  The PROMPT_COMMAND interacts
in a negative way with the -t and -X and -p flags, causing DevStack
not to work.  To solve this problem, this patch forces PROMPT_COMMAND
to default to /bin/true, triggering no changes to the window title
used within screen.  Also this patch enables F19 as a non-FORCE
distribution.

Change-Id: I2414d9e28dd95b69272e132163b29ed83f73b2f6
Fixes: bug #1196340
diff --git a/stack.sh b/stack.sh
index 57b8529..05b53af 100755
--- a/stack.sh
+++ b/stack.sh
@@ -109,7 +109,7 @@
 
 # Warn users who aren't on an explicitly supported distro, but allow them to
 # override check and attempt installation with ``FORCE=yes ./stack``
-if [[ ! ${DISTRO} =~ (oneiric|precise|quantal|raring|saucy|7.0|wheezy|sid|testing|jessie|f16|f17|f18|opensuse-12.2|rhel6) ]]; then
+if [[ ! ${DISTRO} =~ (oneiric|precise|quantal|raring|saucy|7.0|wheezy|sid|testing|jessie|f16|f17|f18|f19|opensuse-12.2|rhel6) ]]; then
     echo "WARNING: this script has not been tested on $DISTRO"
     if [[ "$FORCE" != "yes" ]]; then
         die $LINENO "If you wish to run this script anyway run with FORCE=yes"
@@ -830,6 +830,7 @@
         SCREEN_HARDSTATUS='%{= .} %-Lw%{= .}%> %n%f %t*%{= .}%+Lw%< %-=%{g}(%{d}%H/%l%{g})'
     fi
     screen -r $SCREEN_NAME -X hardstatus alwayslastline "$SCREEN_HARDSTATUS"
+    screen -r $SCREEN_NAME -X setenv PROMPT_COMMAND /bin/true
 fi
 
 # Clear screen rc file