Temporarily disable libgpgme functions because of a bug

`Possible incorrect libgpgme API usage causes a SIGABRT when verifying
signatures #176`

<meli/meli#176>

src/components/mail/pgp.rs

@@ -19,6 +19,9 @@
  * along with meli. If not, see <http://www.gnu.org/licenses/>.
  */
 
+//FIXME
+#![allow(unused_imports, unused_variables)]
+
 use melib::email::{
     attachment_types::{ContentDisposition, ContentType, MultipartType},
     pgp as melib_pgp, Attachment, AttachmentBuilder,
@@ -30,18 +33,24 @@ use std::future::Future;
 use std::pin::Pin;
 
 pub async fn decrypt(raw: Vec<u8>) -> Result<(melib_pgp::DecryptionMetadata, Vec<u8>)> {
+    Err("libgpgme functions are temporarily disabled due to an unsolved bug <https://git.meli.delivery/meli/meli/issues/176>.".into())
+    /*
     let mut ctx = Context::new()?;
     let cipher = ctx.new_data_mem(&raw)?;
     ctx.decrypt(cipher)?.await
+    */
 }
 
 pub async fn verify(a: Attachment) -> Result<()> {
+    Err("libgpgme functions are temporarily disabled due to an unsolved bug <https://git.meli.delivery/meli/meli/issues/176>.".into())
+    /*
     let (data, sig) =
         melib_pgp::verify_signature(&a).chain_err_summary(|| "Could not verify signature.")?;
     let mut ctx = Context::new()?;
     let sig = ctx.new_data_mem(sig.body().trim())?;
     let data = ctx.new_data_mem(&data)?;
     ctx.verify(sig, data)?.await
+    */
 }
 
 pub fn sign_filter(
@@ -53,6 +62,8 @@ pub fn sign_filter(
     Ok(
         move |a: AttachmentBuilder| -> Pin<Box<dyn Future<Output = Result<AttachmentBuilder>>+Send>> {
             Box::pin(async move {
+                Err("libgpgme functions are temporarily disabled due to an unsolved bug <https://git.meli.delivery/meli/meli/issues/176>.".into())
+                /*
                 let a: Attachment = a.into();
                 let mut ctx = Context::new()?;
                 let data = ctx.new_data_mem(&melib_pgp::convert_attachment_to_rfc_spec(
@@ -77,6 +88,7 @@ pub fn sign_filter(
                     vec![],
                 )
                 .into())
+                */
             })
         },
     )
@@ -92,6 +104,8 @@ pub fn encrypt_filter(
     Ok(
         move |a: AttachmentBuilder| -> Pin<Box<dyn Future<Output = Result<AttachmentBuilder>>+Send>> {
             Box::pin(async move {
+                Err("libgpgme functions are temporarily disabled due to an unsolved bug <https://git.meli.delivery/meli/meli/issues/176>.".into())
+                /*
                 let a: Attachment = a.into();
                 debug!("main attachment is {:?}", &a);
                 let mut ctx = Context::new()?;
@@ -124,6 +138,7 @@ pub fn encrypt_filter(
                     vec![],
                 )
                 .into())
+                */
             })
         },
     )