Drop hd5write.default import

This function is not exported by rhdf5 anymore in favour of the
corresponding S3 method.
While sleuth already does not use `hd5write.default` anywhere
(anymore?), it still imports it, breaking the installation on up-to-date
systems.
This commit fixes this by dropping the unnecessary import statement.

Fixes #259.

Author: mschilli87

NAMESPACE

@@ -86,4 +86,3 @@ importFrom(dplyr,"%>%")
 importFrom(lazyeval,interp)
 importFrom(lazyeval,lazy)
 importFrom(rhdf5,h5write)
-importFrom(rhdf5,h5write.default)

R/read_write.R

@@ -358,7 +358,6 @@ trans_to_genes_from_gtf <- function(fname) {
 #'    to use, with 0 being no compression and 7 being the highest supported by this method.
 #'    The default of 6 is a good choice for most applications.
 #' @return the kallisto object \code{kal} invisibly.
-#' @importFrom rhdf5 h5write.default
 #' @importFrom rhdf5 h5write
 #' @export
 write_kallisto_hdf5 <- function(kal, fname, overwrite = TRUE,