Make CpuAffinitySet::applied() method non-const.

According to CPU_SET(3) and, apparently, on some systems (e.g.,
OpenSuSE 10.3) CPU_COUNT macro expects a non-const argument.  The
patch fixes build error on these systems.

=== modified file 'src/CpuAffinitySet.cc'
--- src/CpuAffinitySet.cc	2012-08-28 13:00:30 +0000
+++ src/CpuAffinitySet.cc	2012-08-30 07:08:15 +0000
@@ -50,30 +50,30 @@ CpuAffinitySet::apply()
             success = true;
     }
     if (!success)
         CPU_ZERO(&theOrigCpuSet);
 }
 
 void
 CpuAffinitySet::undo()
 {
     if (applied()) {
         if (sched_setaffinity(0, sizeof(theOrigCpuSet), &theOrigCpuSet)) {
             debugs(54, DBG_IMPORTANT, "ERROR: failed to restore original CPU "
                    "affinity for process PID " << getpid() << ": " <<
                    xstrerror());
         }
         CPU_ZERO(&theOrigCpuSet);
     }
 }
 
 bool
-CpuAffinitySet::applied() const
+CpuAffinitySet::applied()
 {
     return (CPU_COUNT(&theOrigCpuSet) > 0);
 }
 
 void
 CpuAffinitySet::set(const cpu_set_t &aCpuSet)
 {
     memcpy(&theCpuSet, &aCpuSet, sizeof(theCpuSet));
 }

=== modified file 'src/CpuAffinitySet.h'
--- src/CpuAffinitySet.h	2010-11-21 04:40:05 +0000
+++ src/CpuAffinitySet.h	2012-08-30 07:07:36 +0000
@@ -4,31 +4,31 @@
  */
 
 #ifndef SQUID_CPU_AFFINITY_SET_H
 #define SQUID_CPU_AFFINITY_SET_H
 
 #include "compat/cpu.h"
 
 /// cpu affinity management for a single process
 class CpuAffinitySet
 {
 public:
     CpuAffinitySet();
 
     /// set CPU affinity for this process
     void apply();
 
     /// undo CPU affinity changes for this process
     void undo();
 
     /// whether apply() was called and was not undone
-    bool applied() const;
+    bool applied();
 
     /// set CPU affinity mask
     void set(const cpu_set_t &aCpuSet);
 
 private:
     cpu_set_t theCpuSet; ///< configured CPU affinity for this process
     cpu_set_t theOrigCpuSet; ///< CPU affinity for this process before apply()
 };
 
 #endif // SQUID_CPU_AFFINITY_SET_H