bazarr: update expr

* Add runtime program dependencies to buildInputs, instead of setting
that up as part of the install phase. This allows hacking on bazarr
straight from `nix-shell -A bazarr`.
* Add missing preInstall/postInstall hooks.
* Quote shell variables.
* Simplify install path: $out/share/${pname}-${version} -> $out/share/${pname}.
(There's no point in having the version there, and without proper deep
overrides it can also create some problems.)

pkgs/servers/bazarr/default.nix

···
 { stdenv, lib, fetchurl, makeWrapper, unzip, python3, unrar, ffmpeg, nixosTests }:
 
+let
+  runtimeProgDeps = [
+    ffmpeg
+    unrar
+  ];
+in
 stdenv.mkDerivation rec {
   pname = "bazarr";
   version = "1.1.2";
···
 
   nativeBuildInputs = [ unzip makeWrapper ];
 
+  buildInputs = [
+    (python3.withPackages (ps: [ ps.lxml ps.numpy ps.gevent ps.gevent-websocket ]))
+  ] ++ runtimeProgDeps;
+
   installPhase = ''
-    mkdir -p $out/{bin,share/${pname}-${version}}
-    cp -r * $out/share/${pname}-${version}
-    makeWrapper "${
-      (python3.withPackages
-        (ps: [ ps.lxml ps.numpy ps.gevent ps.gevent-websocket ])).interpreter
-    }" \
-      $out/bin/bazarr \
-      --add-flags "$out/share/${pname}-${version}/bazarr.py" \
-      --suffix PATH : ${lib.makeBinPath [ unrar ffmpeg ]}
+    runHook preInstall
+
+    mkdir -p "$out"/{bin,share/${pname}}
+    cp -r * "$out/share/${pname}"
+
+    # Add missing shebang and execute perms so that patchShebangs can do its
+    # thing.
+    sed -i "1i #!/usr/bin/env python3" "$out/share/${pname}/bazarr.py"
+    chmod +x "$out/share/${pname}/bazarr.py"
+
+    makeWrapper "$out/share/${pname}/bazarr.py" \
+        "$out/bin/bazarr" \
+        --suffix PATH : ${lib.makeBinPath runtimeProgDeps}
+
+    runHook postInstall
   '';
 
   passthru.tests = {