ssl: rename md5, sha1 to md5_ctx, sha1_ctx, fix variable shadow warning
Rename variables md5 and sha1 to md5_ctx and sha1_ctx
to avoid a conflict with functions of the same name
defined elsewhere in the library. This fixes compilation
warning with -Wshadow:
ssl_cli.c: In function
‘ssl_parse_server_key_exchange’:
ssl_cli.c:310: warning: declaration of ‘md5’ shadows a
global declaration
../include/tropicssl/md5.h:85: warning: shadowed
declaration is here
ssl_cli.c:311: warning: declaration of ‘sha1’ shadows
a global declaration
../include/tropicssl/sha1.h:85: warning: shadowed
declaration is here