add el7 conditionals, minor deps reordering

mosquitto.spec

@@ -7,13 +7,16 @@ License:        BSD
 URL:            http://mosquitto.org/
 Source0:        http://mosquitto.org/files/source/%{name}-%{version}.tar.gz
 
-BuildRequires:  openssl-devel
-BuildRequires:  systemd-devel
-BuildRequires:  uthash-devel
 BuildRequires:  c-ares-devel
+BuildRequires:  gcc-c++
 BuildRequires:  libuuid-devel
 BuildRequires:  libwebsockets-devel
-BuildRequires:  gcc-c++
+BuildRequires:  openssl-devel
+BuildRequires:  systemd-devel
+%if 0%{?rhel} == 7
+BuildRequires:  tcp_wrappers-libs
+%endif
+BuildRequires:  uthash-devel
 
 Requires(pre):  shadow-utils
 Requires(post): systemd