Try to prevent build with revision detection.

tasks/pathogen-plugins.yml

@@ -145,6 +145,15 @@
 #  become_user: "{{item}}"
 #  with_items: users
 
+- name: Detect previous YouCompleteMe revision
+  register: youcompleteme_revision_old
+  shell: >
+    if [ -d ~/.vim/bundle/YouCompleteMe ]; then 
+      cd ~/.vim/bundle/YouCompleteMe ; 
+      git rev-parse HEAD ;
+    fi
+  ignore_errors: false
+
 - name: Fetch YouCompleteMe plugin
   git:
     repo=https://github.com/Valloric/YouCompleteMe.git
@@ -155,10 +164,23 @@
   become_user: "{{item}}"
   with_items: users
 
+- name: Detect new YouCompleteMe revision
+  register: youcompleteme_revision_new
+  shell: >
+    if [ -d ~/.vim/bundle/YouCompleteMe ]; then 
+      cd ~/.vim/bundle/YouCompleteMe ; 
+      git rev-parse HEAD ;
+    fi
+  ignore_errors: false
+
+- name: Detect YouCompleteMe built plugin
+  debug:  msg="old={{youcompleteme_revision_old}} new={{youcompleteme_revision_new}}"
+
 - name: Detect YouCompleteMe built plugin
   register: youcompleteme_exists
   command: test -f ~/.vim/bundle/YouCompleteMe/third_party/ycmd/ycm_core.so
-  ignore_errors: True
+  ignore_errors: true
+
 
 - name: Build YouCompleteMe plugin
   shell: cd ~/.vim/bundle/YouCompleteMe ; ./install.sh