resp-app: fix broken build after snappy 1.2.0 upgrade

Snappy 1.2.0 changes the signature of the 'Compress' interface. The
new interface is backwards compatible. However, we pull in Snappy
source code via the Git submodules. The submodule provides the old
header file for Snappy (pre 1.2.0) and is used during build
time. While we provide a newer version of the library (1.2.0) with a
different signature of 'Compress'. Since we are using our system
library anyway, we just remove the problematic submodule in the patch
phase.

The commit in question in the Snappy repository is
766d24c95e345d4d06bfd3cc5787c2da3e025fab.

pkgs/applications/misc/resp-app/default.nix

@@ -77,6 +77,7 @@ mkDerivation rec {
       --replace '/opt/resp_app' "${placeholder "out"}" \
       --replace 'target.path = $$LINUX_INSTALL_PATH' 'target.path = $$LINUX_INSTALL_PATH/bin' \
       --replace '/usr/' "$out/"
+    rm -r 3rdparty/snappy
   '';
 
   qmakeFlags = [