Fix lammps patch

When using extra arguments after the name of the log file,
the former could have been overwritten by reeplica suffix.

Bug reported by Marco De La Pierre.

patches/lammps-6Apr13/fix_plumed.cpp

@@ -103,9 +103,9 @@ FixPlumed::FixPlumed(LAMMPS *lmp, int narg, char **arg) :
     else if(next==1){
       // Each replica writes an independent log file
       //  with suffix equal to the replica id
-      char str_num[32], *logFile;
+      char str_num[32], logFile[1024];
       sprintf(str_num,".%d",universe->iworld);
-      logFile=arg[i];
+      strncpy(logFile,arg[i],1024);
       strcat(logFile,str_num);
       p->cmd("setLogFile",logFile);
       next=0;