stdenv/stripHash: print to stdout, not to variable

`stripHash` documentation states that it prints out the stripped name to
the stdout, but the function stored the value in `strippedName`
instead.

Basically all usages did something like
`$(stripHash $foo | echo $strippedName)` which is just braindamaged.
Fixed the implementation and all invocations.

nixos/modules/services/networking/ircd-hybrid/builder.sh

@@ -12,7 +12,7 @@ for i in $scripts; do
     if test "$(echo $i | cut -c1-2)" = "=>"; then
         subDir=$(echo $i | cut -c3-)
     else
-        dst=$out/$subDir/$((stripHash $i; echo $strippedName) | sed 's/\.in//')
+        dst=$out/$subDir/$(stripHash $i | sed 's/\.in//')
         doSub $i $dst
         chmod +x $dst # !!!
     fi
@@ -23,7 +23,7 @@ for i in $substFiles; do
     if test "$(echo $i | cut -c1-2)" = "=>"; then
         subDir=$(echo $i | cut -c3-)
     else
-        dst=$out/$subDir/$((stripHash $i; echo $strippedName) | sed 's/\.in//')
+        dst=$out/$subDir/$(stripHash $i | sed 's/\.in//')
         doSub $i $dst
     fi
 done