Do not check store_status when checking ENTRY_BAD_LENGTH (#1342)

Do not check store_status when checking ENTRY_BAD_LENGTH (#1342)

Before 1997 commit b34ed72 (that introduced the current ENTRY_BAD_LENGTH
"cache"), checking store_status before calling storeEntryValidLength()
kind of made sense because storeEntryValidLength() did not support
STORE_PENDING entries with their unset object_len. Since that commit,
checking store_status does not cause any visible problems (i.e. the code
"works") because ENTRY_BAD_LENGTH implies STORE_OK. However, that
implication is not backed by some fundamental invariant and might
suddenly disappear. Checking two flags instead of one is also wasteful.

No Squid functionality changes are expected.