fix bug where the 'analyze' would try to parse results from non-plists.

For some reason, `-[NSRegularExpression firstMatchInString:options:range:]`
has begun returning nil when there's no match.  This didn't use to
happen, and the docs don't suggest it would happen... it could be a
legit apple bug.

This silences the `Old-style plist parser: missing semicolon in
dictionary on line 2. Parsing will be abandoned.` warnings we've seen.
use xcodebuild's `analyze` action insteaad of RUN_CLANG_STATIC_ANALYZER=YES

Now with Xcode 5, we don't have to use the RUN_CLANG_STATIC_ANALYZER=YES
hack.