[PATCH] invalid "-K" value cause smem ended with IndexError exception

I do "smem -w -K a.txt -R 2048M" and got following error:
zhichyu@w-shpd-zcyu:~/sftw4ubuntu$ smem-0.1/smem -w -K a.txt -R 2048M
size: 'a.txt': No such file
Traceback (most recent call last):
  File "smem-0.1/smem", line 607, in <module>
    showsystem()
  File "smem-0.1/smem", line 361, in showsystem
    k = kernelsize()
  File "smem-0.1/smem", line 77, in kernelsize
    d = os.popen("size %s" % options.kernel).readlines()[1]
IndexError: list index out of range

The root cause is that os.popen("size a.txt") returns only one line.
If the user provides an invalid kernel image file path, I think it's
better to assume the image size is zero than raise an exception.

smem

@@ -83,8 +83,11 @@ _kernelsize = 0
 def kernelsize():
     global _kernelsize
     if not _kernelsize and options.kernel:
-        d = os.popen("size %s" % options.kernel).readlines()[1]
-        _kernelsize = int(d.split()[3]) / 1024
+        try:
+            d = os.popen("size %s" % options.kernel).readlines()[1]
+            _kernelsize = int(d.split()[3]) / 1024
+        except:
+            pass
     return _kernelsize
 
 def pidmaps(pid):