[geary] Remove C warning suppression hack from meson build.

[Michael Gratton <mjog src gnome org>]

commit 33150b22c658022fe1505e6cce2d4398d9decbb8
Author: Michael James Gratton <mike vee net>
Date:   Sun Apr 15 21:56:02 2018 +1000

    Remove C warning suppression hack from meson build.
    
    Meson suppresses all cpp warnings anyway, and valac has recently improved
    on the amount of warning spew its c code generates.

 src/meson.build |    4 ----
 1 files changed, 0 insertions(+), 4 deletions(-)
---
diff --git a/src/meson.build b/src/meson.build
index 472216d..83ccf2c 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -38,10 +38,6 @@ geary_c_options = [
   # Select libunwind's optimised, local-only backtrace unwiding. See
   # libunwind(3).
   '-DUNW_LOCAL_ONLY',
-  # Vala causes a _lot_ of these to be emitted for otherwise valid
-  # code. Suppress them so we can actually see more useful warnings.
-  '-Wno-incompatible-pointer-types',
-  '-Wno-discarded-qualifiers',
 ]
 
 subdir('sqlite3-unicodesn')