chkconfig command in rpm spec file

I would like to use 'chkconfig --del NetworkManager' command in the %install section of a rpm spec file. If I include this command the rpm is building fine but when I install that rpm, it looks that the command does not get executed. After installing I verified using 'chkconfig --list' command and observed the service is till running.

Here is spec file I am using. Please let me know ehre I am going wrong.

%define name disable_network-manager
%define version 1.0
%define release fc

Name:       %{name}
Version:    %{version}
Release:    1%{?dist}
Summary:    Includes the script to disable Network Manager services

Group:      Development/Other
License:    GPL
URL:        www.abcd.com
Source0:    %{name}-%{version}.tar.gz
BuildRoot:  %(mktemp -ud %{_tmppath}/%{name}-%{version}-%{release}-XXXXXX)

%description
sample text.

%prep
%setup -q

#%build

%install
/sbin/chkconfig --del NetworkManager
rm -rf $RPM_BUILD_ROOT
install -m 0755 -d $RPM_BUILD_ROOT/usr/bin
install -m 0755 enablenm.sh $RPM_BUILD_ROOT/usr/bin/enablenm.sh

%clean
rm -rf $RPM_BUILD_ROOT


%files
/usr/bin/enablenm.sh