Add missing `return` statements in scouting requests handler

After an error occurs, we need to stop processing the request. The
code before this patch continued even if there was an error with a
database transaction.

Signed-off-by: Philipp Schrader <philipp.schrader@gmail.com>
Change-Id: I173c23adff420d0c607e455a0cf8cccf3a3e2bd3
diff --git a/scouting/webserver/requests/requests.go b/scouting/webserver/requests/requests.go
index 3c21402..b3e03ff 100644
--- a/scouting/webserver/requests/requests.go
+++ b/scouting/webserver/requests/requests.go
@@ -126,6 +126,7 @@
 	matches, err := handler.db.ReturnMatches()
 	if err != nil {
 		respondWithError(w, http.StatusInternalServerError, fmt.Sprint("Faled to query database: ", err))
+		return
 	}
 
 	var response RequestAllMatchesResponseT
@@ -181,6 +182,7 @@
 	matches, err := handler.db.QueryMatches(request.Team())
 	if err != nil {
 		respondWithError(w, http.StatusInternalServerError, fmt.Sprint("Faled to query database: ", err))
+		return
 	}
 
 	var response RequestAllMatchesResponseT
@@ -236,6 +238,7 @@
 	stats, err := handler.db.ReturnStats()
 	if err != nil {
 		respondWithError(w, http.StatusInternalServerError, fmt.Sprint("Faled to query database: ", err))
+		return
 	}
 
 	var response RequestDataScoutingResponseT