tidy-up: formatting nits

Whitespace and redundant parenthesis in `return`s.

Closes #1029

src/channel.c

@@ -2314,7 +2314,7 @@ _libssh2_channel_packet_data_len(LIBSSH2_CHANNEL * channel, int stream_id)
              && (channel->local.id == read_local_id)
              && (channel->remote.extended_data_ignore_mode
                  == LIBSSH2_CHANNEL_EXTENDED_DATA_MERGE))) {
-            return (read_packet->data_len - read_packet->data_head);
+            return read_packet->data_len - read_packet->data_head;
         }
 
         read_packet = next_packet;

src/crypto.c

@@ -1,5 +1,4 @@
 #define LIBSSH2_CRYPTO_C
-
 #include "libssh2_priv.h"
 
 #if defined(LIBSSH2_OPENSSL) || defined(LIBSSH2_WOLFSSL)

src/misc.c

@@ -935,7 +935,7 @@ int _libssh2_check_length(struct string_buf *buf, size_t len)
 {
     unsigned char *endp = &buf->data[buf->len];
     size_t left = endp - buf->dataptr;
-    return ((len <= left) && (left <= buf->len));
+    return (len <= left) && (left <= buf->len);
 }
 
 int _libssh2_eob(struct string_buf *buf)

src/openssl.c

@@ -3280,7 +3280,7 @@ clean_exit:
     if(md_ctx)
         EVP_MD_CTX_free(md_ctx);
 
-    return (rc == 1 ? 0 : -1);
+    return (rc == 1) ? 0 : -1;
 }
 
 int

src/sftp.c

@@ -632,11 +632,11 @@ sftp_packet_requirev(LIBSSH2_SFTP *sftp, int num_valid_responses,
  */
 static int sftp_attrsize(unsigned long flags)
 {
-    return (4 +                                 /* flags(4) */
+    return 4 +                                 /* flags(4) */
            ((flags & LIBSSH2_SFTP_ATTR_SIZE) ? 8 : 0) +
            ((flags & LIBSSH2_SFTP_ATTR_UIDGID) ? 8 : 0) +
            ((flags & LIBSSH2_SFTP_ATTR_PERMISSIONS) ? 4 : 0) +
-            ((flags & LIBSSH2_SFTP_ATTR_ACMODTIME) ? 8 : 0));
+           ((flags & LIBSSH2_SFTP_ATTR_ACMODTIME) ? 8 : 0);
     /* atime + mtime as u32 */
 }
 
@@ -681,7 +681,7 @@ sftp_attr2bin(unsigned char *p, const LIBSSH2_SFTP_ATTRIBUTES * attrs)
         _libssh2_store_u32(&s, (uint32_t)attrs->mtime);
     }
 
-    return (s - p);
+    return s - p;
 }
 
 /* sftp_bin2attr
@@ -758,7 +758,7 @@ sftp_bin2attr(LIBSSH2_SFTP_ATTRIBUTES *attrs, const unsigned char *p,
         }
     }
 
-    return (buf.dataptr - buf.data);
+    return buf.dataptr - buf.data;
 }
 
 /* ************