package/fswebcam: change tarball compression to xz

Verified equality of underlying tarball with

  tarname=http://www.firestorm.cx/fswebcam/files/fswebcam-20140113.tar
  test "$(wget -qO- $tarname.gz|zcat|sha256sum -)" = "$(wget -qO- $tarname.xz|xzcat|sha256sum -)"

Signed-off-by: Mario Lang <mlang@blind.guru>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/fswebcam/fswebcam.hash

@@ -1,2 +1,2 @@
 # Locally calculated
-sha256	3ee389f72a7737700d22e0c954720b1e3bbadc8a0daad6426c25489ba9dc3199	fswebcam-20140113.tar.gz
+sha256	444d6a8a82102e09e935540c64a731021de36db03e1e74181f41ca6f39aa6474	fswebcam-20140113.tar.xz

package/fswebcam/fswebcam.mk

@@ -5,6 +5,7 @@
 ################################################################################
 
 FSWEBCAM_VERSION = 20140113
+FSWEBCAM_SOURCE = fswebcam-$(FSWEBCAM_VERSION).tar.xz
 FSWEBCAM_SITE = http://www.firestorm.cx/fswebcam/files
 FSWEBCAM_LICENSE = GPL-2.0
 FSWEBCAM_LICENSE_FILES = LICENSE