Add additional grep cmd.

This is necessary to ensure that the `PID` found in `$_gpg_env`
actually belongs to `gpg-agent` and not some other process.

modules/gpg-agent/init.zsh

@@ -5,6 +5,7 @@
 #   Florian Walch <[email protected]>
 #   Sorin Ionescu <[email protected]>
 #   neersighted <[email protected]>
+#   Jakob Hetzelein <[email protected]>
 #
 
 # Return if requirements are not found.
@@ -33,7 +34,7 @@ function _gpg-agent-start {
 # Source GPG agent settings, if applicable.
 if [[ -s "${_gpg_env}" ]]; then
   source "${_gpg_env}" > /dev/null
-  ps -e | grep $(grep GPG_AGENT_INFO $_gpg_env | cut -d: -f 2) ||
+  ps -e | grep $(grep GPG_AGENT_INFO $_gpg_env | cut -d: -f 2) | grep -q gpg-agent ||
     _gpg-agent-start
   }
 else