silence a warning regarding the return value of the fbtl's.

This commit was SVN r32717.

ompi/mca/io/ompio/io_ompio_file_read.c

@@ -80,7 +80,8 @@ int ompio_io_ompio_file_read (mca_io_ompio_file_t *fh,
     uint32_t iov_count = 0;
     struct iovec *decoded_iov = NULL;
 
-    size_t max_data=0, ret_code=0, real_bytes_read=0;
+    size_t max_data=0, real_bytes_read=0;
+    ssize_t ret_code=0;
     int i = 0; /* index into the decoded iovec of the buffer */
     int j = 0; /* index into the file vie iovec */
 
@@ -130,7 +131,7 @@ int ompio_io_ompio_file_read (mca_io_ompio_file_t *fh,
         if (fh->f_num_of_io_entries) {
             ret_code = fh->f_fbtl->fbtl_preadv (fh);
 	    if ( 0<= ret_code ) {
-		real_bytes_read+=ret_code;
+		real_bytes_read+=(size_t)ret_code;
 	    }
         }
 

ompi/mca/io/ompio/io_ompio_file_write.c

@@ -83,7 +83,8 @@ int ompio_io_ompio_file_write (mca_io_ompio_file_t *fh,
     struct iovec *decoded_iov = NULL;
     size_t bytes_per_cycle=0;
     size_t total_bytes_written = 0;
-    size_t max_data=0, ret_code=0, real_bytes_written=0; 
+    size_t max_data=0, real_bytes_written=0; 
+    ssize_t ret_code=0;
     int i = 0; /* index into the decoded iovec of the buffer */
     int j = 0; /* index into the file view iovec */
 
@@ -125,7 +126,7 @@ int ompio_io_ompio_file_write (mca_io_ompio_file_t *fh,
         if (fh->f_num_of_io_entries) {
             ret_code =fh->f_fbtl->fbtl_pwritev (fh);
 	    if ( 0<= ret_code ) {
-		real_bytes_written+=ret_code;
+		real_bytes_written+= (size_t)ret_code;
 	    }
         }