Improve readability of some code. No functional changes.
Improve readability of some code. No functional changes.

* buckets/ssl_buckets.c
  (bio_bucket_read,
   bio_bucket_write): Don't use ctx->bio and bio. They point to the same
     variable and mixing them only obfuscates this already hard to read
     code.

  (ssl_decrypt,
   ssl_encrypt): Document that these functions implement serf_databuf_reader_t.

alex1818/serf,SirJson/serf,soufianeEL/serf,soufianeEL/serf,yesoce/serf,google-code-export/serf,KyleSanderson/serf,stoneCC/serf,zhupan/serf,alex1818/serf,stoneCC/serf,zhupan/serf,x-clone/serf,pengdu/serf,x-clone/serf,SirJson/serf,zhengcq315/serf,pengdu/serf,zhengcq315/serf,yesoce/serf,soufianeEL/serf,stoneCC/serf,KyleSanderson/serf,google-code-export/serf,lazysoez/serf,google-code-export/serf,pengdu/serf,yesoce/serf,alex1818/serf,zhupan/serf,x-clone/serf,KyleSanderson/serf,SirJson/serf,lazysoez/serf,zhupan/serf,lazysoez/serf,x-clone/serf,SirJson/serf,KyleSanderson/serf,pengdu/serf,alex1818/serf,zhengcq315/serf,zhengcq315/serf,soufianeEL/serf,stoneCC/serf,google-code-export/serf,yesoce/serf,lazysoez/serf