Fix default config file name in admin.guide.html.

doc/html/admin.guide.html

@@ -20,7 +20,7 @@ which applications execute, which can number in the thousands.
 <h2>Configuration</h2>
 There a single SLURM configuration file containing: 
 overall SLURM options, node configurations, and partition configuration. 
-This file is located at "/etc/SLURM.conf" by default.
+This file is located at "/etc/slurm.conf" by default.
 The file location can be modified at system build time using the 
 DEFAULT_SLURM_CONF parameter.
 The overall SLURM configuration options specify the control and backup