Configure: style.

Signed-off-by: Piotr Sikora <piotrsikora@google.com>

auto/unix

diff --git a/auto/unix b/auto/unix
index f83173b..0c3ddc5 100755
--- a/auto/unix
+++ b/auto/unix
@@ -264,7 +264,7 @@
 . auto/feature
 
 
-if [ $ngx_found != yes ]; then
+if [ $ngx_found = no ]; then
 
     ngx_feature="dlopen() in libdl"
     ngx_feature_libs="-ldl"
@@ -287,7 +287,7 @@
 . auto/feature
 
 
-if [ $ngx_found != yes ]; then
+if [ $ngx_found = no ]; then
 
     ngx_feature="sched_yield() in librt"
     ngx_feature_libs="-lrt"