gnu: rsem: Update to 1.3.1.

* gnu/packages/bioinformatics.scm (rsem): Update to 1.3.1.
[source]: Fetch from git; remove patch; delete bundled samtools.
[arguments]: Pass make flags; adjust phases.
[inputs]: Remove ncurses and samtools-0.1; add htslib-1.3.
* gnu/packages/patches/rsem-makefile.patch: Remove patch.
* gnu/local.mk (dist_patch_DATA): Remove it.