only try to install nhc if its not already isntalled

Former-commit-id: fe260750

roles/nhc/tasks/main.yml

 ---
+- name: check existing installation
+  stat: path="{{ nhc_dir }}/sbin/nhc"
+  register: nhc_binary
+
 - name: install automake
   yum: name=automake state=present
   become: true
@@ -18,18 +22,21 @@
     copy: no
     dest: /tmp
     creates: /tmp/nhc-{{ nhc_version }}/autogen.sh
+  when: not nhc_binary.stat.exists
 
 - name: build nhc 
   shell: ./autogen.sh && ./configure --prefix={{ nhc_dir }} && make
   args:
     chdir: /tmp/nhc-{{ nhc_version }}
     creates: /tmp/nhc-{{ nhc_version }}/configure
+  when: not nhc_binary.stat.exists
 
 - name: install nhc 
   shell: make install
   sudo: true
   args:
       chdir: /tmp/nhc-{{ nhc_version }}
+  when: not nhc_binary.stat.exists
 
 - name: ensure sysconfig dir exists
   file: dest=/etc/sysconfig state=directory owner=root group=root mode=755