Fix VS 2008 generation with nested folders again

Follow up to r1831, which forgot to adjust one of the call sites of _ConvertSourcesToFilterHierarchy.

Patch from stk.haller@googlemail.com.

R=jochen@chromium.org

Review URL: https://codereview.chromium.org/135903007

git-svn-id: http://gyp.googlecode.com/svn/trunk@1839 78cadc50-ecff-11dd-a971-7dbc132099af
Strip the invalid characters from the string used as mspdbsrv endpoint.

Patch from sebmarchand@chromium.org.

R=scottmg@chromium.org
BUG=335607

Review URL: https://codereview.chromium.org/141163014

git-svn-id: http://gyp.googlecode.com/svn/trunk@1840 78cadc50-ecff-11dd-a971-7dbc132099af