qubes/utils: parse_size: Fix string comparison

This commit resolves a bug which causes strings such as "350MiB" to be
rejected by parse_size, due to the fact that parse_size changes the case
of letters in the input string ("350MiB") to uppercase ("350MIB"), but
fails to do the same for the elements of the units conversion table.

The correction is simple: Apply the same case change to the units
table elements before comparison.

qubes/utils.py

@@ -100,7 +100,7 @@ def parse_size(size):
         return int(size)
 
     for unit, multiplier in units:
-        if size.endswith(unit):
+        if size.endswith(unit.upper()):
             size = size[:-len(unit)].strip()
             return int(size) * multiplier