[Rd] Fixed BLAS tests for external BLAS library

[Simon Guest]

We build R with dynamically linked BLAS and LAPACK libraries, in order
to use the AMD Core Math Library (ACML) multi-threaded implementation
of these routines on our 64 core servers.  This is great, and our
users really appreciate it.

However, when building like this, make check fails on the reg-BLAS.R
test.  The reason for this is that the expected test output is checked
using identical.  By changing all uses of identical in this file to
all.equal, the tests pass.

Specifically, I run this command before make check:

$ sed -i -e 's/identical/all.equal/g' tests/reg-BLAS.R

I suggest that the test is fixed like this in the R source code.

Here is the configure command I use, on CentOS 7:
$ ./configure --with-system-zlib --with-system-bzlib --with-system-pcre \
    --with-blas \
    --with-lapack \
    --with-tcl-config=/usr/lib64/tclConfig.sh \
    --with-tk-config=/usr/lib64/tkConfig.sh \
    --enable-R-shlib \
    --enable-prebuilt-html

cheers,
Simon