Fix for compilation error

~/Arduino/libraries/Sqlite3Esp32/src/esp32.cpp: In function 'int ESP32Open(sqlite3_vfs*, const char*, sqlite3_file*, int, int*)':
~/Arduino/libraries/Sqlite3Esp32/src/esp32.cpp:457:12: error: ordered comparison of pointer with integer zero ('FILE*' and 'int')
  457 |   if( p->fp<=0){
      |       ~~~~~^~~
~/Arduino/libraries/Sqlite3Esp32/src/esp32.cpp: In function 'int ESP32Delete(sqlite3_vfs*, const char*, int)':
~/Arduino/libraries/Sqlite3Esp32/src/esp32.cpp:499:12: error: ordered comparison of pointer with integer zero ('FILE*' and 'int')
  499 |     if( dfd<=0 ){
      |         ~~~^~~

Author: tobozo

src/esp32.cpp

@@ -447,7 +447,7 @@ static int ESP32Open(
   //p->fd = open(zName, oflags, 0600);
   //p->fd = open(zName, oflags, S_IRUSR | S_IWUSR);
   p->fp = fopen(zName, mode);
-  if( p->fp<=0){
+  if( p->fp == (void *)NULL ) {
     if (aBuf)
       sqlite3_free(aBuf);
     //Serial.println("Can't open");
@@ -489,7 +489,7 @@ static int ESP32Delete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
 
     /* Open a file-descriptor on the directory. Sync. Close. */
     dfd = fopen(zDir, "r");
-    if( dfd<=0 ){
+    if( dfd == (void *)NULL ){
       rc = -1;
     }else{
       rc = fflush(dfd);