fix(asdf_install): don't crash when no plugins are installed.

asdf_install

@@ -1,14 +1,13 @@
 #!/bin/bash
 
 set -e
-set -v
 
 source ~/.asdf/asdf.sh
 REQUIRED_PLUGINS=$(cat .tool-versions | cut -d \  -f 1)
-INSTALLED_PLUGINS=$(asdf plugin list)
+INSTALLED_PLUGINS=$(asdf plugin list || echo "")
 
 for PLUGIN in $REQUIRED_PLUGINS; do
-  if [[ $INSTALLED_PLUGINS =~ (^|[^[:alpha:]])$PLUGIN([^[:alpha:]]|$) ]]; then
+  if [[ $INSTALLED_PLUGINS =~ (^|[[:space:]])"$PLUGIN"($|[[:space:]]) ]]; then
     echo "ASDF plugin $PLUGIN already installed"
   else
     echo "Installing $PLUGIN ASDF plugin..."