Wait for reads to finish before reading the result

As requested by @dom96, this fixes an issue seen here: https://github.com/nim-lang/redis/pull/4#issuecomment-312713921

lib/pure/asyncnet.nim

@@ -534,14 +534,14 @@ proc recvLineInto*(socket: AsyncSocket, resString: FutureVar[string],
     var c = ""
     while true:
       let recvFut = recv(socket, 1, flags)
-      c = recvFut.read()
+      c = await recvFut
       if c.len == 0:
         resString.mget.setLen(0)
         resString.complete()
         return
       if c == "\r":
         let recvFut = recv(socket, 1, flags) # Skip \L
-        c = recvFut.read()
+        c = await recvFut
         assert c == "\L"
         addNLIfEmpty()
         resString.complete()