collectd: fix a floating dependence on libvirt

Even though the PACKAGECONFIG of libvirt is used to fix the floating
dependence, but enable-libvirt/disable-libvirt become useless after
collectd upgrade, and libvirt is checked unconditionally, and lead to
a floating dependence on libvirt.

check if libvirt is available only when a user wants to use libvirt
to fix this issue

Signed-off-by: Roy Li <rongqing.li@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>

meta-oe/recipes-extended/collectd/collectd/0001-conditionally-check-libvirt.patch

@@ -0,0 +1,39 @@
+[PATCH] conditionally check libvirt
+
+Upstream-Statue: Pending
+
+check if libvirt is available only when a user wants to use libvirt
+
+Signed-off-by: Roy Li <rongqing.li@windriver.com>
+---
+ configure.ac | 14 ++++++++------
+ 1 file changed, 8 insertions(+), 6 deletions(-)
+
+diff --git a/configure.ac b/configure.ac
+index 923498e..7206095 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -4778,12 +4778,14 @@ then
+ 		with_libxml2="no (pkg-config doesn't know libxml-2.0)"
+ 	fi
+ 
+-	$PKG_CONFIG --exists libvirt 2>/dev/null
+-	if test "$?" = "0"
+-	then
+-		with_libvirt="yes"
+-	else
+-		with_libvirt="no (pkg-config doesn't know libvirt)"
++	if test "x$enable_libvirt" = "xyes"; then
++		$PKG_CONFIG --exists libvirt 2>/dev/null
++		if test "$?" = "0"
++		then
++			with_libvirt="yes"
++		else
++			with_libvirt="no (pkg-config doesn't know libvirt)"
++		fi
+ 	fi
+ fi
+ if test "x$with_libxml2" = "xyes"
+-- 
+1.9.1
+

meta-oe/recipes-extended/collectd/collectd_5.5.0.bb

@@ -10,7 +10,9 @@ SRC_URI = "http://collectd.org/files/collectd-${PV}.tar.bz2 \
            file://collectd-version.patch \
            file://0001-redefine-the-dependence.patch  \
            file://collectd.init \
-           file://collectd.service"
+           file://collectd.service \
+           file://0001-conditionally-check-libvirt.patch \
+"
 SRC_URI[md5sum] = "c39305ef5514b44238b0d31f77e29e6a"
 SRC_URI[sha256sum] = "847684cf5c10de1dc34145078af3fcf6e0d168ba98c14f1343b1062a4b569e88"