change compilation error

Author: xbasel

src/server.c

@@ -2722,7 +2722,7 @@ void makeThreadKillable(void) {
 }
 
 /* Return non-zero if the database is empty  */
-bool dbHasNoKeys(int dbid) {
+int dbHasNoKeys(int dbid) {
     return dbid < 0 || dbid >= server.dbnum || !server.db[dbid] || kvstoreSize(server.db[dbid]->keys) == 0;
 }
 

src/server.h

@@ -3915,7 +3915,7 @@ void debugDelay(int usec);
 void killThreads(void);
 void makeThreadKillable(void);
 serverDb *createDatabase(int id);
-bool dbHasNoKeys(int dbid);
+int dbHasNoKeys(int dbid);
 serverDb *createDatabaseIfNeeded(int id);
 void swapMainDbWithTempDb(serverDb **tempDb);
 sds getVersion(void);