[PATCH 06/12] lib-index: Rename crc32 variables/parameters to hash in strmap

[PATCH 06/12] lib-index: Rename crc32 variables/parameters to hash in strmap

Pure rename - no functional change. The stored 32-bit value is still
produced by crc32_str_nonzero(); only the identifiers change to prepare
for swapping the hash algorithm in the next commit.

recs_crc32 -> recs_hash, hash_key.crc32 -> hash_key.hash,
crc32_r -> hash_r, local crc32 -> hash, *crc32 -> *hashes.

Gbp-Pq: Name 0006-lib-index-Rename-crc32-variables-parameters-to-hash-.patch