Fix typo with the buffer_pool_size parameter

The buffer_pool_size parameter should be a integer value when followed
by a memory unit (eg '1024M', not '1024.1M'). Otherwise the MySQL
doesn't start properly.

Change-Id: I5dfad49a8e44a40ae87c5e8e0b033dcd73dc2837

galera/files/my.cnf

 innodb_file_format=Barracuda
 innodb_file_per_table=1
 {%- if service.innodb_buffer_pool_size is not defined %}
-  {% set buffer_pool_size = '%.2fM'%(grains['mem_total']*0.35) %}
+  {% set buffer_pool_size = '%.0fM'%(grains['mem_total']*0.35) %}
 {%- else %}
   {% set buffer_pool_size = service.innodb_buffer_pool_size %}
 {%- endif %}