Shorten URL creation

The necessary URL can be created with one paste0() call, without
having much impact on readability, etc. Also remove the utils:: from
download.file(), since the function is already imported.

R/getSymbols.R

@@ -1309,16 +1309,14 @@ getSymbols.av <- function(Symbols, env, api.key,
 
     if (verbose) cat("loading", sym.name, ".....")
 
-    url.params <- paste(paste0("function=", FUNCTION),
-                        paste0("symbol=", sym.name),
-                        paste0("interval=", interval),
-                        paste0("outputsize=", output.size),
-                        paste0("apikey=", api.key),
-                        sep="&" )
-    url <- paste0("http://www.alphavantage.co/query",
-                  "?", url.params )
+    URL <- paste0("http://www.alphavantage.co/query",
+                  "?function=", FUNCTION,
+                  "&symbol=", sym.name,
+                  "&interval=", interval,
+                  "&outputsize=", output.size,
+                  "&apikey=", api.key)
 
-    utils::download.file(url=url, destfile=tmp, quiet=!verbose)
+    download.file(url=URL, destfile=tmp, quiet=!verbose)
     lst <- jsonlite::fromJSON(tmp)
 
     #