scripts/Bootstrap: read (P)MODULES_VERSION from Pmodules_version.conf

scripts/Bootstrap/Pmodules_version.conf

+declare -x PMODULES_VERSION=0.99.1
+declare -x MODULES_VERSION=3.2.10
+
+declare -a COMPILER_VERSIONS=( 'gcc/4.7.4' 'gcc/4.8.3' 'gcc/4.8.4' 'gcc/4.9.2' )
+declare -a MPI_VERSIONS=( 'openmpi/1.6.5' 'openmpi/1.8.2' 'openmpi/1.8.4' )
+declare -a HDF5_VERSIONS=( 'hdf5/1.8.12' 'hdf5/1.8.14' )
+declare -a HDF5_SERIAL_VERSIONS=( 'hdf5_serial/1.8.12' 'hdf5_serial/1.8.14' )