Add nfs-utils to dtrace.spec

This dependency was already needed, at least for the test suite for
io-mount-nfs.sh and tst.nfs.sh.

Signed-off-by: Eugene Loh <eugene.loh@oracle.com>
Reviewed-by: Kris Van Hees <kris.van.hees@oracle.com>

dtrace.spec

@@ -148,7 +148,7 @@ Requires:     %{name}-devel = %{version}-%{release} perl gcc java
 Requires:     java-1.8.0-openjdk-devel perl-IO-Socket-IP xfsprogs
 Requires:     exportfs vim-minimal %{name}%{?_isa} = %{version}-%{release}
 Requires:     coreutils wireshark %{glibc32}
-Requires:     perf time bc
+Requires:     perf time bc nfs-utils
 Autoreq:      0
 Group:	      Development/System