MINOR: sample: always set a new sample's owner before evaluating it

Some functions like sample_conv_var2smp(), var_get_byname(), and
var_set_byname() directly or indirectly need to access the current
stream and/or session and must find it in the sample itself and not
as a distinct argument. Thus we first need to call smp_set_owner()
prior to each such calls.
diff --git a/src/sample.c b/src/sample.c
index 7c2d905..6dc62fb 100644
--- a/src/sample.c
+++ b/src/sample.c
@@ -2100,6 +2100,7 @@
 {
 	struct sample tmp;
 
+	smp_set_owner(&tmp, smp->px, smp->sess, smp->strm, smp->opt);
 	if (!sample_conv_var2smp(arg_p, smp->strm, &tmp))
 		return 0;
 	smp->data.u.sint &= tmp.data.u.sint;
@@ -2113,6 +2114,7 @@
 {
 	struct sample tmp;
 
+	smp_set_owner(&tmp, smp->px, smp->sess, smp->strm, smp->opt);
 	if (!sample_conv_var2smp(arg_p, smp->strm, &tmp))
 		return 0;
 	smp->data.u.sint |= tmp.data.u.sint;
@@ -2126,6 +2128,7 @@
 {
 	struct sample tmp;
 
+	smp_set_owner(&tmp, smp->px, smp->sess, smp->strm, smp->opt);
 	if (!sample_conv_var2smp(arg_p, smp->strm, &tmp))
 		return 0;
 	smp->data.u.sint ^= tmp.data.u.sint;
@@ -2165,6 +2168,7 @@
 {
 	struct sample tmp;
 
+	smp_set_owner(&tmp, smp->px, smp->sess, smp->strm, smp->opt);
 	if (!sample_conv_var2smp(arg_p, smp->strm, &tmp))
 		return 0;
 	smp->data.u.sint = arith_add(smp->data.u.sint, tmp.data.u.sint);
@@ -2179,6 +2183,7 @@
 {
 	struct sample tmp;
 
+	smp_set_owner(&tmp, smp->px, smp->sess, smp->strm, smp->opt);
 	if (!sample_conv_var2smp(arg_p, smp->strm, &tmp))
 		return 0;
 
@@ -2211,6 +2216,7 @@
 	struct sample tmp;
 	long long int c;
 
+	smp_set_owner(&tmp, smp->px, smp->sess, smp->strm, smp->opt);
 	if (!sample_conv_var2smp(arg_p, smp->strm, &tmp))
 		return 0;
 
@@ -2254,6 +2260,7 @@
 {
 	struct sample tmp;
 
+	smp_set_owner(&tmp, smp->px, smp->sess, smp->strm, smp->opt);
 	if (!sample_conv_var2smp(arg_p, smp->strm, &tmp))
 		return 0;
 
@@ -2281,6 +2288,7 @@
 {
 	struct sample tmp;
 
+	smp_set_owner(&tmp, smp->px, smp->sess, smp->strm, smp->opt);
 	if (!sample_conv_var2smp(arg_p, smp->strm, &tmp))
 		return 0;