create_arm_debootstrap: Use Debian repos (pin) and remove double wildcard

olinux:~# apt-cache policy u-boot
u-boot:
  Installed: (none)
  Candidate: 2015.04+dfsg1-2
  Package pin: 2015.04+dfsg1-2
  Version table:
     2015.04+dfsg1-2 990
        500 http://ftp.fr.debian.org/debian/ testing/main armhf Packages
     2014.10+dfsg1-5 990
        500 http://ftp.fr.debian.org/debian/ jessie/main armhf Packages
olinux:~# apt-cache policy linux-image-armmp
linux-image-armmp:
  Installed: (none)
  Candidate: 4.0+65
  Package pin: 4.0+65
  Version table:
     4.0+65 990
        500 http://ftp.fr.debian.org/debian/ testing/main armhf Packages
     3.16+63 990
        500 http://ftp.fr.debian.org/debian/ jessie/main armhf Packages
olinux:~# apt-cache policy flash-kernel
flash-kernel:
  Installed: (none)
  Candidate: 3.44
  Package pin: 3.44
  Version table:
     3.44 990
        500 http://ftp.fr.debian.org/debian/ testing/main armhf Packages
     3.35 990
        500 http://ftp.fr.debian.org/debian/ jessie/main armhf Packages

olinux/create_arm_debootstrap.sh

@@ -208,17 +208,18 @@ fi
 
 if [ $INSTALL_KERNEL ] ; then
   if [ $INSTALL_KERNEL = 'testing' ] ; then
-    echo deb http://ftp.fr.debian.org/debian testing main > $TARGET_DIR/etc/apt/sources.list.d/testing.list
-    cat $TARGET_DIR/etc/apt/sources.list.d/testing.list
-    cat <<EOT > $TARGET_DIR/etc/apt/preferences.d/testing
-Package: *linux-image*
-Pin: release a=testing
+    echo 'deb http://ftp.fr.debian.org/debian testing main' > $TARGET_DIR/etc/apt/sources.list.d/testing.list
+    cat <<EOT > $TARGET_DIR/etc/apt/preferences.d/kernel-testing
+Package: linux-image*
+Pin: release o=Debian,a=testing
 Pin-Priority: 990
-Package: *u-boot*
-Pin: release a=testing
+
+Package: u-boot*
+Pin: release o=Debian,a=testing
 Pin-Priority: 990
-Package: *flash-kernel*
-Pin: release a=testing
+
+Package: flash-kernel*
+Pin: release o=Debian,a=testing
 Pin-Priority: 990
 EOT