FindBLAS: Do not look for BLAS once BLAS95 has been found

When BLA_F95 is ON, FindBLAS looks for BLAS95_LIBRARIES (in Intel MKL).
As this is a superset of BLAS_LIBRARIES, if they are found, no further
search in other vendors is necessary.
Status Job ID Name Coverage
  External
passed ghostflow-check-master

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager