Move the generate_breakpad_symbols to tools/posix.

atom.gyp

@@ -488,7 +488,7 @@
               ],
               'action': [
                 'python',
-                'tools/mac/generate_breakpad_symbols.py',
+                'tools/posix/generate_breakpad_symbols.py',
                 '--build-dir=<(PRODUCT_DIR)',
                 '--binary=<(PRODUCT_DIR)/<(product_name).app/Contents/MacOS/<(product_name)',
                 '--symbols-dir=<(PRODUCT_DIR)/Atom-Shell.breakpad.syms',
@@ -535,7 +535,7 @@
               ],
               'action': [
                 'python',
-                'tools/mac/generate_breakpad_symbols.py',
+                'tools/posix/generate_breakpad_symbols.py',
                 '--build-dir=<(PRODUCT_DIR)',
                 '--binary=<(PRODUCT_DIR)/<(project_name)',
                 '--symbols-dir=<(PRODUCT_DIR)/Atom-Shell.breakpad.syms',