libcacard: don't leak vcard_emul_alloc_arrays mem

vcard_emul_mirror_card and vcard_emul_init use
vcard_emul_alloc_arrays to allocate memory for temporary arrays
which will contain elements that in the end will be used one by
one in cac_card_init. The arrays themselves are never stored
anywhere, they are only used as temporary containers. Hence
the memory that was allocated for these arrays should be freed
after use or they will be leaked.
