[mb] drop trusty from buildername in mb_config.pyl

I forgot to rename builder in
https://chromium-review.googlesource.com/c/chromium/src/+/1636662

This is to fix error happening in
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/WebKit%20Linux%20MSAN
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/WebKit%20Linux%20ASAN
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/WebKit%20Linux%20Leak

Bug: 954450
Change-Id: Ic1b7b56f0e54526a2f8910e557e8869dd6600279
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1636991
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Reviewed-by: Fumitoshi Ukai <ukai@chromium.org>
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664666}

tools/mb/mb_config.pyl

@@ -466,9 +466,9 @@
       'Linux MSan Builder': 'msan_release_bot',
       'Linux TSan Builder': 'tsan_disable_nacl_release_bot',
       'Mac ASan 64 Builder': 'asan_minimal_symbols_disable_nacl_release_bot_dcheck_always_on',
-      'WebKit Linux Trusty ASAN': 'asan_lsan_release_bot',
-      'WebKit Linux Trusty Leak': 'release_bot',
-      'WebKit Linux Trusty MSAN': 'msan_release_bot',
+      'WebKit Linux ASAN': 'asan_lsan_release_bot',
+      'WebKit Linux Leak': 'release_bot',
+      'WebKit Linux MSAN': 'msan_release_bot',
       'android-asan': 'android_clang_asan_debug_bot_arm64',
       'win-asan': 'asan_clang_fuzzer_static_v8_heap_minimal_symbols_release',
     },