dumpabi: This would create the directories in the sourcedir instead

dumpabi: This would create the directories in the sourcedir instead
  of the binary dir. Fixed that.
  NOTE: It fails with and without this patch for out of tree builds:

jmayer@egg:~/work/wireshark/svn/build/qt-gtk3> make dumpabi
[  1%] Built target wsutil
[  1%] Generating libwsutil.abi.tar.gz
ERROR: can't find modules
cp: cannot stat `abi_dumps/libwsutil/libwsutil_*': No such file or directory
make[3]: *** [wsutil/libwsutil.abi.tar.gz] Error 1
make[2]: *** [wsutil/CMakeFiles/dumpabi-libwsutil.dir/all] Error 2
make[1]: *** [CMakeFiles/dumpabi.dir/rule] Error 2
make: *** [dumpabi] Error 2
jmayer@egg:~/work/wireshark/svn/build/qt-gtk3>

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@49014 f5534014-38df-0310-8fa8-9805f1628bb7