Avoid variable named 'stat'

Using a variable named 'stat' clashes with the system function
'stat()' causing compiler warnings on some platforms

cc1: warnings being treated as errors
../../src/qemu/qemu_monitor_text.c: In function 'parseMemoryStat':
../../src/qemu/qemu_monitor_text.c:604: error: declaration of 'stat' shadows a global declaration [-Wshadow]
/usr/include/sys/stat.h:455: error: shadowed declaration is here [-Wshadow]
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/qemu/qemu_monitor_text.c

@@ -601,7 +601,7 @@ int qemuMonitorTextGetVirtType(qemuMonitorPtr mon,
 
 
 static int parseMemoryStat(char **text, unsigned int tag,
-                           const char *search, virDomainMemoryStatPtr stat)
+                           const char *search, virDomainMemoryStatPtr mstat)
 {
     char *dummy;
     unsigned long long value;
@@ -625,8 +625,8 @@ static int parseMemoryStat(char **text, unsigned int tag,
             case VIR_DOMAIN_MEMORY_STAT_AVAILABLE:
                 value >>= 10;
         }
-        stat->tag = tag;
-        stat->val = value;
+        mstat->tag = tag;
+        mstat->val = value;
         return 1;
     }
     return 0;