Fix mis-spellings of "separating" as "seperating"

Found by Debian's Lintian tool.

code/botlib/be_aas_cluster.c

@@ -152,7 +152,7 @@ int AAS_UpdatePortal(int areanum, int clusternum)
 	{
 		//remove the cluster portal flag contents
 		aasworld.areasettings[areanum].contents &= ~AREACONTENTS_CLUSTERPORTAL;
-		Log_Write("portal area %d is seperating more than two clusters\r\n", areanum);
+		Log_Write("portal area %d is separating more than two clusters\r\n", areanum);
 		return qfalse;
 	} //end else
 	if (aasworld.portalindexsize >= AAS_MAX_PORTALINDEXSIZE)