s4-ldb_ldif: Don't check for LDB_FLG_SHOW_BINARY in ldb_should_b64_encode

s4-ldb_ldif: Don't check for LDB_FLG_SHOW_BINARY in ldb_should_b64_encode

LDB_FLG_SHOW_BINARY is data representation flag and should
not modify behavior of data checking functions.

This lead to a bug in lib/ldb/ldb_tdb/ldb_index.c as ltdb_index_key()
function relies on ldb_should_b64_encode function to determine
how to process index keys.

Found using following test search:
bin/ldbsearch -H st/dc/private/sam.ldb -b "CN=Deleted Objects,DC=samba,DC=example,DC=com" \
 "(objectGUID=97b52eac-6d89-434d-b935-1e5f2e086ffc)" replPropertyMetaData --show-deleted --show-binary