Fix bash linter warnings in .bashrc_linux64

[KineticTheory]

In environment/bashrc/.bashrc_linux64 line 13:
if [[ -n "$verbose" ]]; then echo "In .bashrc_linux64"; fi
          ^------^ SC2154: verbose is referenced but not assigned.


In environment/bashrc/.bashrc_linux64 line 21:
  target=`uname -n`
         ^--------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
  target=$(uname -n)


In environment/bashrc/.bashrc_linux64 line 37:
target=`uname -n`
       ^--------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
target=$(uname -n)


In environment/bashrc/.bashrc_linux64 line 48:
      module use --append $HOME/privatemodules
                          ^---^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
      module use --append "$HOME"/privatemodules


In environment/bashrc/.bashrc_linux64 line 54:
    if [[ `groups | grep -c ccsrad` != 0 ]]; then
          ^-----------------------^ SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
    if [[ $(groups | grep -c ccsrad) != 0 ]]; then


In environment/bashrc/.bashrc_linux64 line 74:
add_to_path ${DRACO_SRC_DIR}/environment/latex TEXINPUTS
            ^--------------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
add_to_path "${DRACO_SRC_DIR}"/environment/latex TEXINPUTS


In environment/bashrc/.bashrc_linux64 line 75:
add_to_path ${DRACO_SRC_DIR}/environment/bibtex BSTINPUTS
            ^--------------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
add_to_path "${DRACO_SRC_DIR}"/environment/bibtex BSTINPUTS


In environment/bashrc/.bashrc_linux64 line 76:
add_to_path ${DRACO_SRC_DIR}/environment/bibfiles BIBINPUTS
            ^--------------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
add_to_path "${DRACO_SRC_DIR}"/environment/bibfiles BIBINPUTS

For more information:
  https://www.shellcheck.net/wiki/SC2154 -- verbose is referenced but not ass...
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...]
2020-10-13 15:58:29 [ERROR ]   Linter CMD:[shellcheck --color --external-sources environment/bashrc/.bashrc_linux64]
2020-10-13 15:58:29 [INFO  ]   ---------------------------