[Mac] In all the plists, define the LSMinimumSystemVersion based on MACOSX_DEPLOYMENT_TARGET.

ash/shell/cocoa/app-Info.plist

 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
         <key>CFBundleDevelopmentRegion</key>
         <string>en</string>
         <key>CFBundleExecutable</key>
         <string>${EXECUTABLE_NAME}</string>
         <key>CFBundleIconFile</key>
         <string>app.icns</string>
         <key>CFBundleIdentifier</key>
         <string>org.chromium.AuraShell</string>
         <key>CFBundleInfoDictionaryVersion</key>
         <string>6.0</string>
         <key>CFBundleName</key>
         <string>${PRODUCT_NAME}</string>
         <key>CFBundlePackageType</key>
         <string>APPL</string>
         <key>CFBundleShortVersionString</key>
         <string>1.0</string>
         <key>CFBundleSignature</key>
         <string>Ash8</string>
         <key>CFBundleVersion</key>
         <string>1</string>
         <key>LSMinimumSystemVersion</key>
-        <string>${MACOSX_DEPLOYMENT_TARGET}</string>
+        <string>${MACOSX_DEPLOYMENT_TARGET}.0</string>
         <key>NSHumanReadableCopyright</key>
         <string>Copyright © 2012 Google Inc. All rights reserved.</string>
         <key>NSMainNibFile</key>
         <string>MainMenu</string>
         <key>NSPrincipalClass</key>
         <string>NSApplication</string>
 </dict>
 </plist>