rhel: Fix libunwind dev package.

There is no unwind-devel package, only libunwind-devel package is found.
No error is reported with libunwind-devel during compilation.

Fixes: 7e0c91e ("debian and rhel: Add libunwind dev package.")
Signed-off-by: Yalei Li <liyl43@chinatelecom.cn>
Acked-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

rhel/openvswitch.spec.in

@@ -39,7 +39,7 @@ BuildRequires: checkpolicy, selinux-policy-devel
 BuildRequires: autoconf, automake, libtool
 BuildRequires: python3-sphinx
 BuildRequires: unbound-devel
-BuildRequires: unwind-devel
+BuildRequires: libunwind-devel
 
 %bcond_without check
 %bcond_with check_datapath_kernel