Adds googleplaymusic to Info.plist for unittests

testing/gtest_ios/unittest-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>UIApplicationDelegate</key>
         <string>MainApplicationDelegate</string>
         <key>CFBundleDevelopmentRegion</key>
         <string>English</string>
         <key>CFBundleDisplayName</key>
         <string>${PRODUCT_NAME}</string>
@@ skipping 24 matching lines @@
                 <string>googledocs-v2</string>
                 <string>googledocs-x-callback</string>
                 <string>googledocs</string>
                 <string>googledrive-v1</string>
                 <string>googledrive-x-callback</string>
                 <string>googledrive</string>
                 <string>googlegmail-x-callback</string>
                 <string>googlegmail</string>
                 <string>googlephotos</string>
                 <string>googlephotos-x-callback</string>
+                <string>googleplaymusic</string>
                 <string>googlesheets-v2</string>
                 <string>googlesheets-x-callback</string>
                 <string>googlesheets</string>
                 <string>googleslides-v2</string>
                 <string>googleslides-x-callback</string>
                 <string>googleslides</string>
                 <string>gplus-v2</string>
                 <string>gplus-v3</string>
                 <string>gplus</string>
                 <string>vnd.google.calendar</string>
@@ skipping 128 matching lines @@
                 </dict>
         </array>
         <key>UIBackgroundModes</key>
         <array>
                 <string>fetch</string>
         </array>
         <key>SSOAuthURLScheme</key>
         <string>${IOS_BUNDLE_ID_PREFIX}.sso.${PRODUCT_NAME:rfc1034identifier}</string>
 </dict>
 </plist>