Properly init rw locks in cache_entry_t

Since a recycled cache inode entry is cleaned first, which destroys the
rw locks, we must init them for recylced entries as well as newly
allocated entries.

Also, if the initialization of rw locks fails, we must destroy any
already initialized locks before releasing entry.

Signed-off-by: Frank S. Filz <ffilzlnx@mindspring.com>