remote-curl: use error instead of fprintf(stderr)

We usually prefix our error messages with "error: ", but
many error messages from remote-curl are simply printed with
fprintf. This can make the output a little harder to read
(especially because such message may be intermingled with
errors from the parent git process).

There is no reason to avoid error(), as we are already
calling it many places (in addition to libgit.a functions
which use it).

While we're adjusting the messages, we can also drop the
capitalization which makes them unlike other git error
messages.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

remote-curl.c

@@ -396,7 +396,7 @@ static curlioerr rpc_ioctl(CURL *handle, int cmd, void *clientp)
 			rpc->pos = 0;
 			return CURLIOE_OK;
 		}
-		fprintf(stderr, "Unable to rewind rpc post data - try increasing http.postBuffer\n");
+		error("unable to rewind rpc post data - try increasing http.postBuffer");
 		return CURLIOE_FAILRESTART;
 
 	default:
@@ -709,7 +709,7 @@ static int fetch_dumb(int nr_heads, struct ref **to_fetch)
 		free(targets[i]);
 	free(targets);
 
-	return ret ? error("Fetch failed.") : 0;
+	return ret ? error("fetch failed.") : 0;
 }
 
 static int fetch_git(struct discovery *heads,
@@ -949,7 +949,7 @@ int main(int argc, const char **argv)
 	git_extract_argv0_path(argv[0]);
 	setup_git_directory_gently(&nongit);
 	if (argc < 2) {
-		fprintf(stderr, "Remote needed\n");
+		error("remote needed");
 		return 1;
 	}
 
@@ -970,7 +970,7 @@ int main(int argc, const char **argv)
 	do {
 		if (strbuf_getline(&buf, stdin, '\n') == EOF) {
 			if (ferror(stdin))
-				fprintf(stderr, "Error reading command stream\n");
+				error("error reading command stream");
 			return 1;
 		}
 		if (buf.len == 0)
@@ -1014,7 +1014,7 @@ int main(int argc, const char **argv)
 			printf("\n");
 			fflush(stdout);
 		} else {
-			fprintf(stderr, "Unknown command '%s'\n", buf.buf);
+			error("unknown command '%s'", buf.buf);
 			return 1;
 		}
 		strbuf_reset(&buf);